1 piece of ply wood, 1 can of spray adhesive, your choice of felt, a 5x10 piece of carpet padding.

you could round the edges of the wood or leave it square if you want to keep it easy.

spray the adhesive on the plywood, lay the padding down on plywood and trim the excess.

spray the adhesive on top of the padding and lay the felt down. you can tuck the excess under and staple it to the bottom. The rails are a little trickier and you can use any kind of table legs. All in all it would cost you around 100 dollars. I know these are not great instructions but should give you an idea, take em and let your creative side come out.

If you want to buy one I bought one from web page I searched and they had the best selection and best price.