Stamping and Embossing

I'm trying to find cheap cutouts of holiday shapes (wreaths, stockings, Christmas trees, snowmen, etc) that we can stamp on, add stickers to, etc. for a Christmas party. We've looked at foam, but you need special glue, and ink doesn't dry on them quickly. This needs to be a really cheap project that we can do with a LOT of kids. I was hoping for card stock, but can't find bulk shapes on-line. Does anyone know where I might be able to get some? (or have other super easy, mass produced, ornament making ideas instead? )