You know those great little 4" x 4" non-stick work surface sheets that are recommended for holding metal clay pieces as they dry?
They are expensive - 4 of them for $4.50 at Metal Clay Supply. That works out to 74 square inches at $.07 per square inch.
Whole Lotta Whimsy has 2 6" x 6" pieces for $4.60 (That's 72 square inches, at $.064 per square inch.)
Compare that to this bargain - a 23" x 16.25" sheet (which you can cut into whatever sizes you need) for $9.99! That's almost 374 square inches - at less than $.03/ square inch.
I found mine at Bed, Bath & Beyond, but they are also available online at Target, Amazon.com, Sears and probably at many other kitchen supply stores. They are all oven friendly, but not for use inside kilns.