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.
The easiest way to see that is to go to HREFs and look at the anchor text. It reveals right away whether or not the site has been spammed. You also want to see if it’s been SEO’d too much. Right? In this case, it’s not because it has a brand name here and some natural keywords, but if the number one anchor text was like, cell phone management system and then the next one was like cheap cell phone management system, you’d know that the anchor text was manipulated and probably overly SEO’d. So, what you want as a site that has a natural link profile.

The most popular place by far is ExpiredDomains.net. The main advantage of ExpiredDomains.net is that it aggregates data from a lot of different auctions and websites around the web. There are also paid services like DomCop. DomCom helps you identify worthy domains faster by displaying some additional data points that allow you to vet domains easily and in a unified interface. And finally, there are services that curate domains they believe are worthy such as JustDropped.com’s newsletter.

Park the domain with a domain parking service. Since you may not have content to put on the site, a parking service puts up a dummy page with ads. When people visit and click on the ads, that's money for you. This method works best with popular keyword domains that get lots of traffic. In most cases, you will not have control over what ads appear on your domains.[5]
You can still buy two word or three word domain names incorporating your target keywords. Moreover, there are millions of domain names out there which haven’t been used at all and are bound to expire soon. All such domains keep coming back to the domain marketplace. What more, there are useful tools available to research and filter through such expired domains.
What type of business are you considering of building something on using the domain name?Is it something you believe in and willing to put your all, how much can the monetize with the website, etc..Ask yourself much questions before proceeding to finally selling it.Also, it doesn’t matter if a different company is using a different extension.It means you have upper hand to get their traffic if you build something using the .com.Good luck
Domain names expire when someone decides to stop renewing it. They may not be available to register immediately. We update the search index every night, so some names may already be renewed or re-registered. Some may become available in a few days. Some registrars, like GoDaddy, will let you buy a name that one of their own customers expire immediately. When you find a name you like, just click on it to try backordering the name!

Just like a property listing, except much simpler, domain marketplaces are basically massive lists of domain names that are up for sale. The process of using them is simple. Buy a domain and park it, then list your domain on the marketplace for a price you’re willing to let it go for. Once the domain is sold, the marketplace takes a cut and then passes on the remaining funds to you.
Parking: While your domain is just sitting there waiting for its new owner, you might as well take advantage of it. Parking sets up automated advertising on your domain so that you earn money every time someone views/clicks on an ad. This could be especially useful if your domain is an expired one that’s already receiving traffic. Services that offer parking include Sedo, GoDaddy, 1and1 among many others.
This is similar to house flipping, where a home is purchased and fixed up in order to sell for a quick profit. Unlike house flipping, however, there is essentially nothing to be done with the domain name in order to increase its value. Therefore, the key to a successful domain flip is being in the right place at the right time in order to acquire a valuable domain name before it is given a premium price.
The first thing you need to do is signup at Namejet in order to get your account (signup is free).  You can then use their search functionality to sort through all the upcoming domains for auction.  Place bids for $69 on the ones you want to go to auction for.  If you bid on 100 different domains for $69 each, and there is 50 bidders for each auction you need to understand you aren’t going to owe any money, you are not committing $6,900 to Namejet.  By entering that $69 you are getting an entry into the live bidding when the 30 days expire.  Only if you are the ONLY bidder on a domain would you automatically win the domain and owe $69 to Namejet.
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.
Yandex replaced TCI with SQI (Site Quality Index). SQI looks similar to TCI, so I re-used the old TCI field, however all values are now the new SQI. Not all domains are checked yet, but all that had TCI > 0, are now switched to SQI and all newly added domains are also checked for SQI (starting today). Updating all domains will take a couple months.
Similarly, for adult items which are theme based you go for similar domain names that are suitable for such businesses. Like for bridal cakes for bachelorette we need to wish them luck sop for a bachelorette cakes and other party items site the names can be like http://www.luckonluck.com. Though somewhat it could be suitable also for book making sites. But better luck is needed to a bride after all and for HEN parties ladies need luck.
Also with the domains, a name which can be cheap for one can be worth gold for the other. Permute the letters in your domain name and try contacting and eventually selling out to organizations that run under those names or contain the letters within. Companies would be keenly interested in buying out the domain names that matches the product's name. Hint : Look for companies on LinkedIn
Unfortunately, you probably won't like my tips. You need to look for quality domains at a good price and be willing to hold on to them to get your money back or know when you've invested wrong and get rid of them. Quality is in the eye of the holder, and believe me, I've looked at plenty of domain portfolios that the owner just knew were million dollar domains but in my opinion, they'd be hard pressed to get anyone to take them off their hands for just the registration costs. You have to figure that most of the best .com domains were registered in the 90's, and those are the ones you typically see the 6-7+ figure sale prices on. I'm not saying there isn't money to be made because there is. But it does take time, research and money, and maybe in some cases a little bit of luck. If you're thinking of getting into the industry, I recommend digging into the resources provided by Michael Cyger on http://domainsherpa.com and from there, moving to some of the other big blogs such as TheDomains.com or

As mentioned earlier, knowing the potential value of a domain name is an invaluable skill. By adhering to basic guidelines such as those I listed above and through some of your own research, you’ll be able to pick names that offer you a higher chance of flipping them more easily. Remember, a net profit of $100 is still a profit, you must start somewhere.

Buying a website is a risky job especially if the investment is big. My first experience was a big fail. So after some time spent on Flippa I found out about a site called Safe Site Buying which I heard that was created by super sellers from flippa and got a coupon code "flippa50" which was supposed to give me a huge 50% discount. This deal looked pretty good to me so I tried it. They provided me with a full report, 20 pages long and with their own subjective opinion. They were very helpful. When you want to spend more than $2-3000 on a website this service is a must if you ask me.
Be careful! When searching for domains, it might be tempting to, for instance, buy mcdonalds.net (if it were available) and then try to sell it to McDonald's. The logic here would be that they own the .com and wouldn’t want anyone to own the .net and use their name, right? Also, it’s a big name so there’s gotta be a biiiiiiig payday comin’, RIGHT? Wrong, and wrong.