I've got a LOT of 8x10 3 part boxes...I saved these from going to the recycle bin in hopes that people here might need them. If you are in San Francisco, come by my shop: 448 Haight Street, Noon-6pm. Shipping would probably be not worth it, but if you really want them I can look into it. As for price, I'll be like the Met--donation that is up to you!
If you wrap them kind of like a gift and put two loops of packing tape around them (making a cross), the shipping would be nominal since they'd be less than 12" on any side and exceedingly light. I don't even care what happens to them cosmetically, the "gift-wrapping" aspect would only be to take the brunt of the adhesive.