If you could describe which formulas, and why they are troublesome, I could give a better answer. Otherwise I suggest two resources:
Wikipedia -- some people question its reliability but I've found it accurate as to scientific questions. It may give a more advanced discussion than you're looking for, though.
Google -- try searches like "FREE physics homework help", and maybe the particular topics you need, such as "FREE physics homework help motion".
You might be clear as to what you need: explanation of a concept, how to use a formula, how to solve a problem, and so on.
Beware: many sites will try to charge you for service.
I've tried the site below (just now). It seems to be decent, and they didn't try to charge in advance. I don't know yet how quick or accurate they are.
PhysicsClassroom is a good website that you might find helpful. They have written tutorials and visual videos, as well as practice and a q-and-a section.