Tink u could make one with NIC cubes but i dont think there a good price in the UK, t
here are some indoor rabbit cages around ur price range but most of them are crap, full of plastic or only have top openings or openings rabbits trip over,
I think a dog crate is best with some blankets in it,
u could also make one using the thick plastic coated wire mesh u can buy at garden centres think its about a fiver a sheet, but I'm not sure how many u would need or how strong it would be