These poly mailers are awesome for anyone doing moderate to heavy shipping. They are very affordable at just around 10-12 cents per bag. While being cheap they still hold up very well while in transit. The great thing about these is you can use them for other shipping purposes like covering an item for some extra protection. Instead of just throwing something in a box, you can look a little more professional if you seal it up first with one of these. At such a low price per unit, it's hard to not have these at hand.