What I did was to look for good value second hand routers nearby to me on Kijiji (Canadian classified market similar to Craigslist) then narrow them down by OpenWrt support.

Using this method, I bought 3 wireless routers 2.5-3 years ago for a total of about 50 CAD. They have been running as dumb wireless APs (https://openwrt.org/docs/guide-user/network/wifi/dumbap) ever since, to great effect.