Sample size n=1, but I was 2 years out of undergrad (and 5-6 years out of my BCPM courses) and I used the TBR books, Nova Physics and AAMC material to get a balanced 37. It probably cost me $500 at most and I did not have to retake the MCAT either. A prep course costs >$1000.
Again, sample size n=1, but some further perspective on OOS schools:
I applied to 24 schools, 4 in-state (I'm a CA resident so I skipped the top-tier public schools since I wouldn't get in), 6 OOS and 14 private.
The results so far:
In-state 1 interview (waitlisted), 1 pre-interview hold
OOS 3 interviews (1 acceptance, 1 pending, 1 declined by me), 1 pre-interview hold
Private 7 interviews (1 acceptance, 1 waitlist, 3 declined by me, 2 pending), 2 pre-interview rejections, 1 pre-interview hold
The OOS/private rate of interview are about the same and exceed that of in-state!