Wireless Router as an Access Point
Access points are pretty expensive, but home routers are cheap. The paradox here is that the router does more “stuff” than an access point. The router contains an access point, a switch, and a small router between all three. The access point just has the access point.
You can take an old consumer internet router and have it behave like an access point with a switch. It’s pretty easy. Give it an IP address on your LAN, and then turn off DHCP and UPnP. That should be all you need. Just remember to plug the ethernet cable into the “LAN” switch rather than the “Internet” uplink port. You don’t want anything going into the uplink, because traffic is being routed from the antenna to the switch, which then talks to another router, which carries it toward the gateway.