It is negotiable depending on the intensity of the work, the timescale, and also whether it's a one-shot job or an extended arrangement for a project.
The range has been $15-$30 (US dollars) so far for different jobs.
Since I am in college now and have several classes and hours of assignments each day, the timeframe is most important as I fit in work (work which is vital to me since as a college student I NEED MONEY)