I have two rules when searching for domains.

First, I never search for a complete name. I use www.namedroppers.com that allows partial name searches. E.g. if I'm looking for 'coolwidgets', I'd search for "olwidge".

And second, if I see a potentially interesting domain, I grab it right away, without any worries about the cost -- I'll just drop it a year later if I don't need it.