The easiest and least time consuming option is to 301 redirect the old domain to your existing site. This tactic obviously works best if both sites are in the same sector and are targeting the same keywords; otherwise, if you have a pet supply site and you buy an old Texas Hold 'Em poker site, a redirect probably might raise some eyebrows among the search engines. If, however, your site is brandnamepets.com and you buy onlinepetsupply.com and 301 redirect the domain over, you're inheriting a lot of topical and appropriate links.
If the third party in question does not have the trademark rights they claim, or it is not a very strong claim. In most cases, the third party will need their trademark registered with the US Patent and Trademark Office (USPTO). The USPTO website has a trademark search engine that you can consult. This may also require a cybersquatting attorney to help determine if the trademark claim is strong enough.
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.
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.
If you’re patient enough, you can discover at least four to five very good .COM domain names at attractive prices. However, you’ll need to carry out some research and find out the right places where they may be available. I’ve seen that such .COM deals can also be bagged from popular domain marketplaces like Flippa.com, or from the private portfolio portals of sellers, provided you employ the right strategies. You can contact the domain owners directly too. There’s no harm in emailing them directly to negotiate the prices.
Unfortunately, most domain names take at least a couple of months to sell, especially without an attached website. Thus, there is no need to become discouraged if your domain name does not sell immediately. Most people make the mistake of quitting their domain speculation endeavor after waiting for several months to sell without success. In reality, domain name squatting can be just as profitable, and it is a valid form of long term investing.
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.