We get paid for all scrimmages here in Connecticut. $50.00 each (two officials), or $33.00 each (three officials, with one official rotating out every period), for six periods (maximum of two hours).
Years ago we used to volunteer, and sign up, for scrimmages. Most were free, some paid a small stipend (twenty bucks for gas, laundry, lunch), some gave us pizza, grinders, T-shirts, etc.. Then our state interscholastic sports governing body made some changes because many sports (not basketball, but sports like field hockey, lacrosse, etc.) were having a difficult time getting officials to work their scrimmages, so now all scrimmages, for all sports, are paid, and all are assigned by assignment commissioners, in the same manner as games.