I just was looking online yesteday for a cheap EPP foam 3D plane. Came across this Techone Spirit that is being offeredon saleby www.84hobby.com
I haven't received it yet, but all the reviews I've read and videos that I've watched looks like a great plane expecially for under $40. The best part is that it's made out of EPP foam so it will be very durable. I have a couple wings from CrashTestHobby made from EPP and the stuff is almost bulletproof.
Here's a link to the plane that I'm buying, but if you want something smaller, check out the other ARF planes or complete packages from www.84hobby.com