How large an area do you have to cover? what distance from router to the farthest device? Are lines of sight clear or are there walls in the way, if so what construction (eg concrete block, simple drywall)? How simple or complex are your security requirements (such as VPN, spam filtering, encryption)? Do you need multiple networks or is it OK to have everyone on the same local network? How much interference do you get from other wifi networks in the building? How important is mass file transfer locally? How fast is your external (WAN) link? How much local computer-to-computer / computer-to-device traffic is generated and is it steady or bursty?
Lots of questions to be answered before you can get a good answer.
If what you need is basically a home router in a home-sized area that can handle a half-dozen or so devices, with nothing especially demanding going on, you can put any decent router in there. TP-Link, Netgear, etc. For example, the TP-Link C50 is cheap, has decent if not exceptional range, and will get the job done if you don't have massive amounts of local network traffic.