I've ordered things from walmart.com and had them shipped to the local store. Works great and saves on shipping!
Shipping costs from sewforless work out better if you order more than one can at a time.
I calculated the costs of the two cans. The smaller Walmart can is $1.61 per oz, and the larger sewforless can is $1.68 per oz. The per oz cost of the sewforless probably goes down considerably if you order 2 cans at one time. If I am remembering correctly, the larger can was enough for about 3 full-size to queen-size quilts.