Target used to have a large selection of Foodsaver bags on the shelves. We are an hour from the nearest store, so we don't shop there very often, but I remember seeing them.
As was said, sign up on the Foodsaver website, they will send you emails about sales. This is the best you will do, if it was possible to get them cheaper, my wife would know about it. She buys enough to get the free shipping, when the price is right.
She was just complaining the other day, that as soon as you order, they send out a better offer. It's not a fluke, it happens everytime. She has tried canceling the order and getting the better deal, but they won't do it. They told her the only way to cancel is to refuse the shipment. So now, she'll make a small order, wait for the better deal email, order a large amount at the better price, and then refuse the first shipment.
It sounds like a stupid way to do business, but they probably don't run into many people, willing to go to the trouble to save a buck, as she does.
Anyhow, the first sale price you get from them is a better deal than you'll find anyplace, but the second offer is way better.
YMMV,
Tim