Here is some things to consider when buying or getting a domain from an auction:
- How easy will it be for people to remember?
- What purpose does the domain represent; a business, organization, from a country (you want to show your association with a country, or a more specialized need like .tv or .info?
- How hard will it be to build up traffic to the site, will buying an auctioned domain (that has accurate stats) you may get some traffic from those people/search engines/blogs... that previously indexed the default url of the domain.
- Is a name that you want only available via auction?
- You should diligently search the web if you choose to buy a domain that there is not well established ill-will towards the domain in the Web community. It is best not to buy an image problem and have to turn it around; better to start fresh.
A Daughter site of sitepoint.com, https://flippa.com/ is a safe place to purchase an auction site. Many people find GoDaddy.com a good place to purchase and manage their domains. Personally I like easydns.com as they have fantastic support and great DNS tools for managing the different public DNS features you might need 'like stealth forwarding' as an example.
Hope this helps.