A Ubiquiti solution works great and you should be able to do it for less than $400 .
You need a
Ubiquiti Edgerouter (router) ($63) and a
Unifi AP (wireless access point)($100). When setting it up, you connect a computer / laptop via hardwire ethernet. Once it's setup, it runs on it's own without a controller and you can make changes with a computer through wifi. Unlike most routers where you access them through a web browser, Ubiquiti requires you to run a dedicated application on your computer in order to interface and make changes.
One Unifi AP (wireless access point) works great and covers a huge area. If you use a Ubiquiti Edgerouter (router) with it, the Edgerouter supplies the power to the AP over the ethernet cable.
As far as the complexity, it's generally moderate unless you run into issues. The system seems to be geared towards commercial / businesses and gives you setup options for most everything (i.e. they are assuming someone with some networking experience is setting it up). I found their customer support to be good and wished I called them earlier when I ran into issues

.