nowhere to buy that few frozen, smallest i have seen is 50 i believe although the bigger the feed the less in a packedge. check out
http://www.bigcheeserodents.com or
http://www.bigappleherp.com those seem to be most popular on here. rodent pro seems to be no good from peoples experiences.
maybe try buying a larger frozen rat and see how the snake takes that. mine is on small rats right now (40g) maybe once every 10 days or so, its been a while since hes shedding.