I think that's the main thing: if your snakes will take FT, then ordering in bulk online (and having a vacuum sealer) is much cheaper and easier. However, if all your snakes don't accept FT and the prices at the stores around you are too high, then breeding your own can be worth the work.

The mice at the store I frequent are well priced, but the rats (since they sell more, having more customers with large boas and pythons) are a bit pricey...at least for me. Now that I have three adult BPs, I realize that my original idea to feed multiple mice just isn't economical even though I've been breeding my own mice.

Also, if you (like me) can find really good deals on bulk bedding or food then it can cut costs. Using tubs instead of tanks or cages for the rodents is also much cheaper.

In the end, it comes down to: how many snakes you have to feed (I have 10), how much room you have for a rodent colony, budget restraints, whether your snakes will take FT or not (my corns will, my BPs will not...yet), and time to clean rodents as well as snakes.