Clear Stock for Vacuum-Formed Canopy

Go to a Party store and/or some super markets and pick up some clear plastic plates. They are about 0.02" thick and vacuform nicely. They also come in many colors and packs of 10 or up to 50 from Party stores and much less expensive than sheets. I use them. Here's one source:

http://www.partycity.com/product/clear+tableware.do

Edit: Here's a link to using plastic dinner plates for vac forming -1 of a series:

https://www.youtube.com/watch?v=oJVFxK5pseA

I use the lids from those tubs of pre washed greens at the Safeway.

It isn't cheap, but you get Arugula!

Thanks for your help, gents! I'm going to give the plates and containers a try.  I don't mind having some Arugula around!    

Not too long ago I saw an ad for the sheets cut to size and hole-punched to fit the Mattel machine.  As far as just sheets of clear plastic of several types, Micro Mark does carry them.

http://www.hobbylobby.com/Crafts-%26-Hobbies/Hobbies-%26-Collecting/Tools-%26-Blades/-030%22-Clear-Plastic-Sheets/p/97972

This stuff works for me- Found at most hobby shops or easily obtained online.