Lots of domain name companies sell them for a few quid, but you need to check the small print to see how much it would be to transfer the domain to another supplier, remove supplier advertising, or renew the contract at the end of two years. It can vary quite a lot and often cost considerably more than the original purchase price.
Once you've got the domain name you just forward it to your flickr, zenfolio, WAB profile page etc...so when someone puts in
www.yourname.com they end up on your
Gallery page
Stu