RTB food size?

[Wildernessmedic]

Thinking of getting a RTB and I'm trying to figure out how I will handle food. All the F/T on rodent pro seem to be sold in 50 or 100 count boxes only, and the shipping is way over priced.

How many of each size is normal before moving up? Say X amount of fuzzies, x amount of adult mice, small rats etc. I don't want to buy a ton of something that will be too small in a month or so. I'd like to get a years supply frozen so it's convenient and always available. I'm in no hurry for it to grow and I don't want to over/powerfeed it. I don't mind having some leftover but if I buy a box of 100 mice I don't want to end up with 50 of them left if its too big for them before they're out.

Any advice? They all seem pretty expensive locally. I guess I could travel to somewhere they are cheaper, but a ton and just kill them all to freeze myself?