Their are rules and guidelines for being enslaved. If you wish to be free try the following :
Ask your master nicely to free you.
Climb to 10x your masters PR and you can declare your own freedom, if you have trouble with this enlist the aid of an ally.
Someone else may also enslave you and they can free you but be careful as this may be considered battle arranging. Don`t exchange any fleet info, make sure you have a fleet, and announce the need for it on public chat.
Also as was mention by Dellz your master doesn`t make a dime unless your making money by spending turns. Also please keep in mind if your master vm`s you can pm an Admin and he should be able to free you.
Good luck and good hunting
{DG}