My rationale for buying used is that basically normal consumers typically do not buy Ubiquiti enterprise products - so anyone who does is someone who has experience with technology and will take care of it well.
I haven't had a chance to test this out yet, but I hope it works!
I picked up an Edgerouter X SFP for $40 on FB Marketplace (retails for $99), the guy selling it is a mobility architect. It came in great condition. After I bought it I found an Edgerouter PoE5 ALSO being sold for $40 - this retails at $275. I don't really need it, but I've thought about buying it since it's so cheap anyways. I'm also going to purchase an AP AC Long Range for $50 - this retails at $109.
The Edgerouters do not come with an AP built in, so you have to buy one separately. I don't mind doing this since I think it's easier to mount an access point than it is to mount a router since you have to worry about less wires (just ethernet if the ap can be poe'd).
For about $90 total I'll have an enterprise router and AP that'll work much better than the cheap sagecom router I'm renting from my ISP.