If you are feeling ambitious, you can link each of your domain names to its matching “buy it now” purchase page at one of the marketplaces. Another more sophisticated option would be to “park” your domain with one of the leading domain parking companies, such as DomainSponsor or SmartName and enable their built-in “for sale” message and contact mechanisms.
GoDaddy offers a variety of benefits when you choose to buy or sell your domain with us. We have a unique Auction bidder verification process that protects both buyers and sellers from any kind of fraudulent activity. We also offer a handy Investor mobile app that allows you to watch auctions in real time and view their history (including number of bidders and how much they bid), all from the convenience of your smartphone.

I have one domain name which I never used it and it has .com and I later discovered there is another company with similar name but with .net and they are doing good as once they approached me to sell them my .com which I never did as I had plan to start something which didn’t materialize . its been 11 years now I have maintained the name now I have two options.

Aside from places where you buy and sell domain names, there are some companies around that support the business of domain flipping. GoDaddy is one of the bigger names out there that does. There, you can not only trade domain names but also park those you’ve bought. The buying, parking and selling is relatively painless and all you must give up is a small percentage of your selling price.
Domain flipping is the art of buying a good domain name at a wholesale price and successfully selling it at a resale price and making a profit. I’ve been helping clients flip domain names for over 10 years. The skills needed to be successful is some working capital, knowledge of domain valuations and a good information flow from a trustworthy domain broker who knows the landscape and can help source you the best deals.

Review Web Archive’s versions of the website: Examine the website’s history and how it looked like using the Web Archive. What was it about? What did it offer? This is useful for a variety of different reasons. It could inspire you as to who a good potential buyer might be (by analyzing the website’s content), and it could also signal some red flags in case the domain was being used for anything shady.
  Since starting SEO back in 2009, it has become very difficult to rank brand new domains. Unless you are building a brand, it's highly recommended that you start every new money site with an expired domain. Additionally, if you're building a PBN, you should only consider using expired domains. The problem is good domains start at $50 a piece, and anyone charging less is either full of sh*t or selling garbage domains, and I mean that. If it sounds too good to be true, it probably is. DomCop has a great offer that all of you buying expired domains should consider. For the price of a couple domain names, you can use DomCop for a month, snag some excellent domain names, which would otherwise cost you thousands of dollars. If you're considering expired domain software and don't have the knowledge to program your own crawler, I'd lean towards DomCop.   
As far as flipping domains for a profit is concerned, there are certain domain names that are worth a lot of money. For instance, Hotel.com and Business.com have been reportedly sold for $11 million and $7 million respectively. Now even though coming across such golden domain names seems more like a long shot, you can still make a decent amount of money if you choose to buy and sell domains as a part-time business opportunity.
I founded this site back in 2007. I lost $50 to a data entry scam when I was still in college. I felt ripped off and had no recourse, but to suck it up and pull an extra shift delivering food to make ends meet.I setup this site so no one would have to go through the same experience I went through. I wanted to stop scam artists from preying on the vulnerable and help regular people learn the true, legitimate ways of making money online.

To join, you’ll need to purchase an annual GoDaddy Auctions membership for $4.99 a year. Once you’ve purchased a membership, you can take advantage of member benefits such as our Auctions Tools, which can help you prepare before buying or selling any domains. After joining the auction community, you’ll quickly learn how to navigate the world of domain buying and selling and can begin to make money by investing in domain names.

Let’s play this out with a real example. Say you’re familiar with the real estate market in Tempe, Ariz., and you have the opportunity to purchase tempeapartments.com for $200. This might be a good deal. Tempe has a lot of rental property; it’s  a competitive market; and there’s ample turnover in the apartment space because the city is home to a major university. Ask yourself:

If you buy a dropped domain from Snap or Namejet, the backlinks seem to be worthless for SEO.  They are valuable for traffic if it's targeted to your site.  Go ahead and 301 redirect into your site because it's the traffic from the back links that is worth something.  I use the Google URL builder to redirect these names so you can see the domain the traffic is coming from.
Also, Sedo.com, makes millions a week selling domains,even in the past week[3]! If you want to sell here, I would probably use a paid category or featured listings, one of my category listings, got 44 views in just 1 week but still waiting for a sale this month, hopefully. I would not really on this as a business, unless you add web development to it, and also, be sure to check that you are making a good profit, say within 6 months!
The great thing about this is that it’s kind of like a metasearch engine for all the places that you can find expired domains around the web. First, let’s look at deleted domains. Okay? To do that, you go click on the deleted domains button here and then click on any top level domain that you want to get. I prefer .com because it’s obviously the most common top level domain.
Parking the Domain Name: When you park a domain name, every time someone enters IHateCold(.com) into their web browsers, a page with a few ads and sales info is shown. So you’re letting the visitor know that the domain is for sale and you make a few cents on the ads displayed for views. There are several domain parking services for when their buying and selling domain names, but I’ll go into that in another post.
Contact Potential Buying Companies: With my domain IHateCold(.com) I will email the marketing teams of some of the large winter clothing companies and let them know of the available domain to buy and a few potential slogans they could use with the domain name. This is a very “I’m here to help you” scenario that I’m curious to see how it plays out. They’ll have to learn about the domain name for sale somehow, right?

@ib2 @T-3D I've been a domain investor for over 10 years and have been very successful at it. There's a lot more that goes into it then just registering a domain name and hoping it will sell. You can list your domains on Godaddy auction listings or on premium listings, I've had a lot of success with those. Some good resources are namebio.com, dnjournal.com, namepros.com and others.
The first is the link profile I and actually took this example carbondsystems.com because it looked like a pretty good choice. It’s from 2003. It has some links, some age and it’s in DMAS and looked at the link profile in DMAS. So, you just copy and paste the domain,  the home page it to here, click on the search links button and this will show you all the links to that site.

Timothy Shim is a writer, editor, and tech geek. Starting his career in the field of Information Technology, he rapidly found his way into print and has since worked with International, regional and domestic media titles including ComputerWorld, PC.com, Business Today, and The Asian Banker. His expertise lies in the field of technology from both consumer as well as enterprise points of view.
Yes! Selling domain is an emerging trade and no wonder if it can develop into an exchange. www.DomainX.org has been initiated with this view. There are some good ideas in the comments regarding which names to buy and how to grow their value. However one must not forget that it also involves a recurring cost (annual renewal) and keeping many of them might become difficult if you are not really selling at least a few to cover it. Enjoy free listing at DomainX.org.
1) pending delete auctions.  These are domains that were not renewed and are going through a pretty complicated drop process.  You can backorder these names at the auction venues and then each attempts to "catch" the dropping domain.  If one is successful you win the domain at $59 if you're the only one to backorder the name.  If more than one person backordered the domain a 3 day private auction is held.  Once the domain goes through the drop process, the back links have pretty much zero SEO benifit to the new domain owner.
Let’s just say for example we wanted this site, crystalgiftsworld.com. It looked good based on our analysis and we’d head over to Snap Names, Nameja is another one and what these service do is they have special technology on their site that allows them to try  to register a domain on your behalf over and over again. Okay? If you tried to do that your IP would get banned, but they have some system where they know how to do it just enough to get the domain, but not enough to get blacklisted.
This wonderful piece of information about buying expired domains is simply mind-blowing and I did not know about that before. It is easy for every one to understand about the topic with the pictorial representation. I feel sad that you lost around $400 due to Fake PR, but this article will surely help others save them from any sort of inconvenience.

Buying domains or registering domains–what’s the difference? There are many ways to acquire a domain. While available domains can be registered with any domain provider, rights of use from already-registered domains have to be purchased from their current owners. You can find different market places and auction platforms online that are tailored to these purposes. This kind of domain trade is...

Length: This is pretty self-explanatory. Generally the shorter the domain name, the more valuable it is. This difference in value decreases exponentially as the name gets longer, though. For instance, the difference in price between 3 and 4 letter domains are significant, while the price difference between a 7 and 8 letter domain would usually be much less significant.