Ugh, I used to buy so many URLs.
When I was setting up my first ever project, whatsitliketo.com, I bought dozens of them:
(Some come up as .shopshutterart.com domains because I put them in as add-on domains.)
15 URLs! Probably £8-10 each. Madness.
Simple tip for project-makers: just buy one URL. Google deals with misspellings pretty well, and most people just search for the sites they want anyway. Only spend your money where it matters.