Well they say it is based on your experience...and ranging from $7 to $13. I had no prior experience w/Disney, but was able to get the PI w/my experience, I guess. I am in the Finance dept and my pay is between $11-$12.
I think it really depends on the department. My friend is an architectural engineer PI this semester and her pay is $16, which sounds a lot higher than any other wages I've heard about so far.