Once upon a time... really. We were driving along a country road when I spied a pretty little stand of wild oats. Nearby was a stand of panic grass and a little farther on were a few stalks of wild asparagus fern.
I couldn't resist. We stopped and I got out and cut them off at the base tehn put them in a plastic bag in the trunk. This became the basis of my large winter bouquet. Since the grasses were dry already, they didn't shed seeds or fall apart after they were put into a gallon antique jar I found at a garage sale. I dust it with a feather duster now and then and that's all the maintenance it takes.
The biggest cost to this huge bouquet was the jar, which cost around $2 if I remember correctly. Cheap autumn and Thanksgiving decor, indeed, especially so since the bouquet has served its purpose for over 15 years now.
Other than that, I decorate with winter squashes and apples, nuts and leaves and whatever catches my eye as I roam around outside.
It's rock bottom frugal to look to nature and to the things that you already have on hand to decorate for Thanksgiving. Leave the fake leaves and the plastic pumkins at the store and go for real and awesome and simple and cheap...
Seasonal Decor from Nature
5 quick and cheap Thanksgiving décor ideas
Decorating for Fall