you can breed your own feeders if you want... livebearers are a good choice, ie guppies or platies would be a good choice... it will take a while to get a large stock of them so this is a long term solution FYI. I breed my own and its been a couple months and they are still only giving me maybe 5 feeders every two weeks at most.
The key behind growing your own feeders is you can control their diet (thereby control the nutrition of the predatory fish) and you can be sure that you are introducing no diseases from the lfs. Start with 2 males to five or 6 females for a good start.