A basic DIY store shed will do them nicely - under £100 sometimes, with enough height fro you to get in to clean, shelf half way up to perch on, an old drawer filled with straw to lay eggs in, a big stainless steel bowl (dog bowl) for water and a large flat tray, taken off the ground with bricks, for their food. Nothing fancy, easy to find, easy to clean, not expensive! Plastic (or metal if any risk of rats) bin for food, plastic cup to measure out feed each day. Wormer every so often. Bob's your uncle - have fun!
Annie