Feeder roaches, primarily, with E. posticus, the orange head, the species most commonly cultured.
They breed prolifically, cannot climb smooth surfaces, do not fly meaningfully, and convert low-cost food into more roaches with almost no input. That is the entire proposition and it is a good one. E. distanti is kept more as a display animal.
Prices are at the floor and cannot rise, since any established colony produces continuous surplus. Buy a starter culture rather than individuals and you have solved the problem permanently. The only reason to look at listings for this genus after the first purchase is if you want a different species, not more of the one you have.