What a pain....well you could always use the Kraft paper for wrapping presents and tizz it up with stickers/stencils/potato prints. Not sure what thickness butchers paper is in the USA...but if you could get a sheet (free if you smile sweetly) from your local butcher you could do a test run and see how you go with that. It is a good size and cheap.
Aside from that you may be able to find a thin, transparent vilene type material...I know there is a product here which people use to draft dress patterns, they sell it by the metre and it is very cheap.
Good luck and happy quilting.