Some times I like to play with transparencies that Ive printed using my laser printer. I use them for things like stencils and such. I have HP brand printable overhead transparency sheets. They make them for inkjet too, though I have not used them. The laser type that I have is nice and thick. I have contact printed them before and it works fine. Maybe you can give that a try, just grab them from a local office supply store for testing.
Another option would be just to get lith film or xray film, and use that. I took a quick look online and staples has the printable transparency sheets for 50-70 bucks for 100 sheets, lith film such as ultrafine's 8x10 100sheet pack is only $80 on amazon.