Paying out of pocket so want to know if I should buy Proactiv OTC or use benzoyl peroxide from rx?

Rx. Proactiv is a "one size fits all" product. If you happen to be the "size" that it fits, it will work; otherwise it won't. Prescription products are chosen by dermatologists specifically for the type of acne that you have, so you are much more likely to get products that work the first time around.