Sams usually has them pretty cheap, but I think they are half pans.
+1, you can get both half and full pans, either used or newGet mine at used restaurant supply
I bought a full pan off amazon and I love it! It's a MF to store and clean, but it's basically like adding 2' to my counter. Don't recall how much I paid for it, but it was pretty cheap- all aluminum, nice and light. I use it for prepping and slicing just about all of my cooks.
if you want full size sheet pans 18 X 26 (used for commercial baking) they are $9.22 each
http://www.equippers.com/vollrath-full-size-aluminum-sheet-pan-18x26/9003.asp
if you want full size steamtable pans 2-1/2' deep they are $10.25 each
http://www.equippers.com/full-size-anti-jam-standard-weight-stainless-steel-food-pan-2-1-2-deep/200f2.asp
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