We use a collapseible nylon/plastic cooler. It is zippered around the top, has a shoulder strap, and folds up when your done using it. It does not take up a lot of room in luggage. Its about 1" deep, 2" long, and 1" wide. We got it a Walmart several years ago and its still going strong. We used to take it to WDW (pre-Poly) and it worked out
great...
We took the nylon collapsible cooler (about the size of a laptop bag) with rollers and filled it each day with new ice. Folded it up when we were done and took it home and use it when we go to the market. About $20 at Coscto, Sams, Wal-Mart etc..
