I recently bought a pen similar to the amazon one above on ebay, the seller was reducing stock and was selling them for less than £20 with free postage. If you are putting it on carpet you would need a waterproof sheet to stand it on like a shower curtain or plastic table cloth then a fleece blanket on top. I've got a wood floor so I use a home made fleece cage liner, as its padded wee doesn't often go right through but if it does I can just wipe the floor.