If you can wait until maybe September, there’s a new AppleTV coming which will lead to a lot of second hand ones hitting the market. 

https://www.apple.com/nz/shop/product/fn893x/a/refurbished-apple-tv-4k-128gb-3rd-generation-wi-fi-ethernet?fnode=8f281fa13cfe2bee81ff85641429a81084964b581b3f8bd4d857f078cd86cbf8c757d815c95cdceecb2ca352900d80165aac22940828a3f5b6f345847db4015ce6dc40e24837dd2078a00d37715f352cb6bb51689cd65257882b450b4c733fa3