Working jobs next to studying represents a large portion of student’s main source of financing. The Studentenwerk Thüringen does not directly offer its own employment agency; however, it does support students as much as possible in their search for employment. Basic information can be found on the German Studentenwerk (DSW) webpage and on this flyer.
Principally, you have the right to work as many jobs and earn as much money as you want. Anyway is there a limit for student’s own maximum income respectively the volume of the period of employment, look at the information of the Deutsches Studentenwerk. However, such limitations for income and period of employment do exist for different social services and social benefits, which concern you and your family (BAföG, Child Money, Tax Free Allowances, Insurance Premiums). You should also keep in mind that employment which does not pertain to your studies will impede the duration of your studies and not only to a slight extent.
Concerning the tax burden, there are, for one, differences between employer and employee contributions, and aside from that there are also differences between the kinds of taxes, insurance, (incl. nursing insurance), pension insurance, unemployment insurance and income tax (incl. solidarity tax).