You might want to shop around, (if you haven't already), for some. Prices can vary so much. Coupons can help a great deal.
Also, you can supplement their feeds with certain feeds, etc. I supplement ours with small brim I catch in a trap. The extra protein has been good for them and
the cost of brim to me is "0". NOw that it is winter, they REALLY seem to enjoy it. It also brought their egg laying up.
Some folks on here have even tried growing their own meal worms.