Anytime you are told that you are "getting great exposure" in lieu of compensation, you are getting ripped-off and you are establishing that your price for your services is $0.00.
How much is a 10% raise on free? Oh yeah....
I worked with an "indie" that did the same thing with their friends and hangers-on; the "privilege" of working the door, the merch table or "stage managing" for nothing; you get to tell everyone that you were part of the event AND you get no money, nor free merch; I spoke up about how unfair this is and I no longer work with these folks.
Look, how many threads exist on this board where we're telling a burgeoning mixer/recordist that doing free demos in the hopes of landing bigger contracts never works out; we read these stories all of the time; "I tracked demos for a band as a goodwill gesture and they went to another studio and paid that guy instead" or "A band I was recording for free left with the tracks and is paying another studio to mix them" and the like.
You should be compensated for your work; I won't play for free with acts that are local to me; why in hell would I play for free with someone that is somewhat established?