That's not £30? And preferably doesn't have animal print on the sides 
www.amazon.co.uk/dp/B016QOBB8S/ref=cm_sw_r_cp_apa_JQMZxbKVMB8KF
We have been using similar cardboard ones which they love, for sharpening and lying on. They scratch them to bits though and even with daily hoovering there are constantly bits of shredded cardboard everywhere.
Thanks!