Buyforhome via eBay offers this 3x5-Foot American Flag for $2.94 with free shipping. Excluding the below mention, that's a buck under the best deal for a 3x5-foot US flag elsewhere and the lowest price we've seen for such a flag. It's made of polyester and features two brass grommets.
Don't mind waiting on your deal? Perfect277 via eBay offers a similar flag for $2.05 with free shipping. It ships from Hong Kong and requires three to eight weeks for delivery.