Whats the best drugstore foundation? please help!?

ok so i dunt know wat kinda skin i have cuz my skin is really dry on some ares and sumtimes it gets oily and i breakout. And its summer and i go out with my friends evryday and my skin is breaking out really bad :( and im so desperate to use any make up. But idk wat to product to buy. So please help me! wat are the foundations that are good for acnes, that has a great coverage and wont make my skin oily and make me breakoutt? thank you(: