Where can I find inexpensive fall centerpieces?

I am getting married in the fall and I need to find inexpensive centerpieces. I figured if I looked around now, I might find them cheaper. I don't have a lot of money to spend on them. I can probably only spend up to $15 or $20 for each one, at the very most. I would prefer centerpieces that involve pumpkins somehow, but they don't have to. Any help would be appreciated. Serious answers only, please. Thanks so much!!