I'm not 100% certain, but it looks like this might be what you're looking for:

Edited link out - It's NOT what he was looking for and might prove misleading.

Yes, unfortunately, color inkjet transparencies run about $0.50/each or more!

The cheap transparencies can be had for $0.15/each or so. No idea how well they will work in an inkjet, let alone color ink.

Andorax, those are for copiers... They will not work for inkjet printers. Inkjet printer transparencies have a film coating which absorbs water-based inks, permanently; toner-based transparenceis (for copiers and laser printers), rely on the toner melting into their plastic, for pernanency. They are radically different animals. If you use toner-based transparencies in an inkjet printer, the ink will not absorb into the plastic, but it will form mini-droplets on the surface, which will either smear, or dry up, on the surface, in tiny little balls, looking nothing like the image you were expecting... Cheers!

Unfortunately there is no way to get transparencies cheap. I bought a box of 50 from Office Depot for around $30. The upside is that 50 will get you extremely far.

I was able to get smaller packages of transparency film for printers at the local Michael's Craft center, they cost more per sheet (I think something like 75 cents a page), but you could by them in packages of 10 sheets. I ran out doing the lighthouse mod to CWU.

The Auld Grump

Walmart sells sheets of 10 (8.5 x 11 - US LETTER) of Inkjet Printer transparencies for around $5 - $6.00. It's made by Hammermill.

I've used them in my HP Photosmart 1315 and the Epson's we have at work. The inks in both printers covered just fine and held decent detailing. I've used it successfully on various projects. The only "extra" thing I do to mine is spray them with Clear Coat for extra durability. (Not a requiement - as the ink adheres to the surface about as well as it does paper. The only notable exception is that it took a few extra minutes for my HP ink to completely dry)

-Floyd