I always order my feeders online (at least for my corn snakes and initially with my ball pythons before I started feeding them live). You need to order from a company that does SMALL orders. Some only do bags of 100. You need to find a place that does 10-25 per bag (I use Loxahatchee Rodents and LOVE them). I would get one bag of pups, one bag of weaned rats, and one bag of smalls.

Like others have said, if you find you only needed 15 rat pups before moving onto weaned rats, offer two in one sitting or feed more frequently until you use those up.