Free, and staffed by physics grad students. Basically, all of the 100-level physics tutors pool their office hours together to have a help desk of sorts staffed most of the day. Though it is nominally for PH10x, most of them will not mind if you come by with PH253 questions.
Also, straight from the senior purchaser at the supply store:
As of right now, we have 6 books at our Ferguson Center location. We do have another 12 books on order. They are scheduled to be delivered Monday the 25th.