Most popular auctions with expiring domains are at godaddy, namejet, snapnames. Search for expired domains name its very easy if you have domains list. With a bit luck, you can drop good one with PR5 cheaper like $200, just need to know which domain have not fake pr. List of domains are not free, but updated dailly with aprox. 50.000 new expiring domain names.
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.
I recommend Go Daddy premium and Afternic. Once you get it listed at those two places then do a redirect so that anyone who types the URL goes to one of those two, for-sale pages. I would suggest a price of $500 to $2,000. You might get lucky and attract a buyer in the next year or two. After two years, if it doesn’t sell I would just stop renewing it.
This is a little bit on the grey hat/black hat side of the spectrum. But the fact is building a blog network with expired domains flat out works. The only issue is getting those cream of the crop domains without going broke. This video will walk you through tested strategies and techniques you can use to find powerful, yet affordable, expired domains.

Premium Domain names are domains that are already registered, but are available for sale at a higher price. Sometimes it will be an individual selling the domain, or it could be the domain registry (Like Donuts Inc. or Radix) selling their top quality inventory at a higher price point. These domains can be priced anywhere from a couple extra bucks to millions, depending on the domain name, the level of interest, or the amount of traffic it organically receives.

Hi guys, just a thought, you do not need to build traffic to the domain yourself, you can always buy expired domains, best to subscribe to a paid service like (so you are the first to know) or a free one, and in this way, you can get old domains that have traffic. You could use these domains for parking, getting advertising income or even to sell. I have noticed, that domains that were not hot in the past, can still be hot now, just use Google Trends to type in the keyword, and you will see its future projections. 
In theory, you could technically acquire a domain for $10,000 and be able to sell it for $100,000. You could also acquire a domain for $10 and be able to sell it for $100,000, $10,000… or $100, you get the picture. Because of this, it’s hard to recommend a perfect starting budget because your strategy, experience, and the pace at which you learn will hugely affect your buying and selling decisions.