Well, I've had one corn snake for a few months, and just recently bought four baby balls. I have a small mouse colony started (1 male, 9 females), plus I'm looking to start a small ASF colony. I'm planning on breeding snakes later, but right now, I only have four baby balls and one juvie corn snake. I had actually bred mice before for the corn, but quit because I couldn't handle my allergies any longer. Anyways, I think you could actually work a breeding colony of feeders for any amount of snakes that you're feeding, without costing too much. One thing I've noticed with pre-frozen critters from a supplier is that they all look like they've been constricted by a snake already, so, even if it does cost $.10 more per feeder, I feel it's worth it to produce HEALTHY feeders. But, if you breed wisely, I believe even in a small snake colony, you can breed your own feeders for cheaper than purchased.
The stickied thread of cost doesn't seem to actually calculate bedding/food for the actual number of rodents kept.

I'll have to check into my files and work out a calculation for small time feeder breeding.