What does the 'tbh' stand for?

"to be honest"

Any tips on choosing a reasonably-priced but effective one? My
budget is extremely tight, but if it's the best thing to do, I'll do
it.

None at all i'm afraid, but your first question to them should be "are
you Part P qualified"

I'm guessing most that you find in the local paper won't be - and it's
now a legal requirement.