Ziploc is offering free samples of its "Ziploc Brand Fresh Shield Freezer Bags" through a promotion with Costco.
You don't have to be a member of Costco to get the free bags, but the offer does require an e-mail address that Costco will send you offers to.
Ziploc advertises that the freezer bags have double zippers to make them the company's tightest seal ever. They can be used to defrost and reheat food by opening the zipper one inch to vent.
Delivery of the sample takes four to six weeks.