This is a bit unusual - I need some pieces of foam (say 2 squares of about 30-40 in and 3-4 in thick) to dress up a friend as a sandwich (we're campaining for cheaper sandwiches in our university's shops).
You'd think foam would be something relatively cheap, but most sources are ridiculously expensive - there are services that cut upholstery foam to shape, but it costs a fair bit, and we're ona shoestring budget.
Any ideas where I could get something like this cheaply? Alternatives welcome. (thought of sticking some camping mats together, using an old mattress, anything...)