Can anyone recommend a Macro/Ring Flash for the K7?

I know there's the PENTAX AF-160 FC Ring Flash, but at $5-600 I'm looking for a cheaper alternative. Looked on *bay, there were so many types. I'm guessing the $70 2 battery LED ones won't be bright enough for chasing insects. I don't know how much GN I need, or how truthful those claims are.

Any good ones for chasing insects out there? I want enough power to be doing f10 at ISO400 or lower. At close distances using my tamron 90mm macro, this should be reasonable?