The organic farm I work on charges 29 cents a pound. It usually works out to 2-3$, but they are smaller than the grocery store ones. My kids don't care about the size as long as they aren't presented with the option of a giant one.
We also grew our own this year. Too late for you obviously, but you might try it next year. We got 7 pumpkins. Total cost was about 2$ for one pack of seeds.