I found them for $3.00 each, they came in boxes of 6 so I bought 2 of them. They are a common fire brick, I see them at the Tractor Supply store, and a Worth W Smith store, I think Home Depot might have them too. I bought my Clayton 1537G used, 8 years old. Had all the original fire bricks in it all cracked from wood abuse. Some in 4 or 5 pieces but all of them were retaining their shape and were tight. I burned my first year with it like that, then replaced them for this year.