Fibrament is good because it can be cut to size (my buddy got a Fibrament as a replacement stone for his old Blodgett pizza oven). There are also cordierite kiln shelves that are food grade, but I haven't used those. Either of these options will be well under $100. All things considered, that is cheap. No need to go with Chinese or Mexican tiles that may or may not contain lead, cadmium, etc., etc., just to save a few bucks.