Quit it.

I assume u r 20,21 and making 15$/hr.That's good. You should be satisfied for now. You r just a student.

Stealing in itself is a bad deed. Yes,we all want more money,there is never a  limit to it.For that either u work hard and make more  money or look for another job but stealing is lowering yourself in your own eyes as well as others if u ever get caught(u might be....Paap dhuri bata karauchha). Honesty and hard work as well as self control will take you a long way in your life.Even if u see others doing it,u don't do  it. You know what ,in our life we need self control too.It helps us a lot.

Hope u'll stop doing it and choose a right  path .Ultimately,that's the only thing that will give you peace of mind and happiness in your life :-)

My two cents..........