Here are some suggestions for alternative sources of income.
Private tutor If you have good grades in some of your subjects, and if you think you can effectively pass your knowledge on to other students, then private tutoring may be the thing for you. The money is pretty good, you can work from home and set the term of the class to work with your college schedule. Just publish an add online in the student communities and that should do it.
Why not try some web work? The money is of course better if you have some advanced computer skills, however even with basic skills you can find work online that is fairly paid. So from simple data entry jobs on some of the freelance sites to website designs, if you have a computer and internet connection, you have the tools to create some additional revenue through this channel.
Sales How about selling your second hand goods that you no longer need. Mobile phones, chargers, laptops, clothes, shoes, stationary etc. Some money is better than none, especially if you never use those things too!
Refereeing Are you still active in sports, or maybe you were in your teenage days? The best way to get all the information is to go to your local sport club and see what requirements they may have. It does not take a lot of time, and it is fun especially if you are a fan of that specific sport.