Where are you buying your feeders? If you get them online, they should come out much cheaper, therefore being more economical than canned foods, anyways. You should be able to get 500 crickets, delivered, for $20. That should last about two weeks for a single growing dragon. (Lasts me three weeks, in addition to 400 phoenix worms). You can get them even cheaper if you got 1,000; I just don't like to fuss with quite that many crickets. Collard greens shouldn't cost you more than $1 a bunch, which should last you a week for a young dragon.
Ordering online should come out to 2-5 cents per cricket, in comparison to 5-10cents in a pet store.
I would avoid canned/packaged/prepared foods at all costs..
ETA: Ok, I do understand that some beardies eat 100 crickets a day, so 500 may not last quite that long!