I use a lamp shade XD I cut a door way out of it and removed the metal/fillings in it washed it and then used duct tape to cover up the endings and top so it can be dark for them to hide in, I find most of my eggs in there now they really love it I use it since I can't find a Teepee shaped one.
I use small pet igloos just because I had them left lying around from rescue guinea pigs and such. Before I dug them up I used a cardboard box type hide(actually a pet castle, hehe).
When I'm able to expand my quail operation I'll likely use plastic flower pots with doors notched in the rims because I have some of those laying around unused too.