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.
Lately I've noticed a lot of questions in Q&A centering on purchasing expired domains. A lot of our members have expressed interest in buying old domains for a variety of prices (some are cheap, some are going for upwards of $50k) and want some advice on what to do with the domains once they've been purchased. I'm no domainer, nor am I an expert in such a business tactic, but I generally recommend one of three different options for an expired domain (and would love to hear more if you've got any).
Expired domains are domains that have been registered by individuals, businesses, or organizations, but aren’t renewed after the contract ends, or are deliberately terminated. That means that they available for re-registration. There are many reasons why someone would choose to abandon a domain; one reason could be that the web project failed, or that a domain portfolio went into liquidization. Domains can also end up becoming free due to the owner receiving warnings for possible trademark infringement. Re-registering can also result in legal consequences.
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.