En Anglais, cheap loans is an OK search phrase.
The more important thing is this:
Do the French (or anyone else) actually search for "prets pas cher?"
If so, how many times per month?
Also, what is the CPC and ad competition level?
The name sounds awkward. While the name is grammatically correct, I think prêt bon marché would be more appropriate. But it still looks odd to me. It's not the adjective/keyword I would use for credit. The best would be to get input from native speakers.