Earning extra cash for college

I'm a sophomore in college and am looking to earn some extra money to help pay for books and other college expenses. I already do work study but I don't earn vey much with it. Does anyone have any suggestions for earning a little extra money that doesn't take up a lot of time?

I was thinking about tutoring elementary or middle school kids since I'm on the deans list, but I'm not sure how to get the word out without spending any money. Any ideas on this too?

Thanks for all your help. I'm open to anything at this point, so I will look into any and all suggestions. Thanks so much!