You can buy 100 mealworms from a pet store for about $5. It doesn't amount to much so if you're serious about feeding them to your chickens, the financially responsible thing to do would be to breed them yourself. Which is what we're doing.
You take your squirmy worms and dump them into a high sided container (like a small fishtank) with a bunch of wheat bran and a cut up potato. I change the potato out once a week and add more bran as I see it depleting.
The wormy thing (larva) turns into a pupa which then turns into a darkling beetle.
The beetle lays on average 500 eggs, which starts the whole cycle again. Once the new larva hatch we'll start feeding some to our chickens.
I bet you're feeling hungry now aren't ya?