Work-Study
Work-study is a form of financial aid where you can work while in school. Your work schedule is arranged around your class schedule. Most work-study opportunities are located on your school's campus which makes the location convenient.
The work opportunities are just like actual jobs where you will gain valuable experience working around professional individuals. As an added bonus, you might gain valuable work experience related to your major; seldom occurs but is possible. With all that said, not every school participates in the work-study program.
With this in mind, check with the financial aid office of your school to see if they have a work-study program in place or something similar.
Work Hours & Payment
Each work-study program is set up differently. The requirements for hours worked per week tend not to go any higher than twenty total hours; at least at the time I participated in the program. The amount paid per hour will differ too, and is determined by the school.
When I was in the program years ago, my work schedule revolved around my classes and payments were disbursed once a month. Every school is different with how they handle payments.