I think it depends on what you store, should be 20-30 years for beans and rice, but with the SHTF crap creeping up on us, don't think you will have to wait that long.

It looks like Mountain House Foods meat items only store for 5-8 years.

Looks like the Tenn guy who posted here has an ebay- 50 1 gal mylars+ oxy absorbers for 25.00 shipped.