I agree with most of what I've read in this thread, but it really depends on the individual store. My girlfriend and I both keep mantids, and the Petco near my house sells only the hydeis in a small tube, while the one near her house only sells melanogasters in decent-sized pots which have lasted for a pretty long time. I agree with Phil that feeding your mantids just with stuff from Petco is likely to get expensive - but I still know which day of the week the one near me gets its crickets.