If your brick stables aren't in use and can be made secure at night, I'd use them instead of shelling out for an expensive coop of any kind. You may need to add perches if there isn't anywhere obvious for them to roost, but branches or cheap timber would do the trick, and some shavings on the floor under them that you can sweep out. As for laying, a couple of cardboard boxes or fruit trays would do - they just want them to have a bit of privacy and some kind of soft bedding - shavings, hay, straw, whatever you have. Mine have rabbit hutches dotted about the garden but as often as not I'll find a couple behind a round bale or inside a builders bag of loose hay, under nettles, bushes..
It's quite a lot easier to find eggs if your hens aren't free ranging but I like them that way and a fox here can only get one in a visit, not slaughter the lot in a confined area. Your ladies will probably lay in the stable before you let them out and you could make a secure (roofed) run outside the door so they can be let out without hassle, or use a window as a pophole if there is one.