There are many different types of foundation that all have different finishes and coverage.
Foundations can also be significantly different depending on what type of budget you have to work with also.
Try a few different drug store brands to start off with.
A few to try:
Revlon Color Stay
Neutrogena- natural radiant look
Loreal Bare Naturale

I would recommend www.bareminerals.com You have to layer it, but it makes your skin look very clear. It's great to wear during the summer, because it stays dry, even if you're sweating.