[jlgaddis]

Motorola (Canopy) used to make a bunch of 900 MHz (ISM) radios that were popular with WISPs. They weren't technically Wi-Fi but a proprietary protocol.

I can't recall if Ubiquiti ever had any 900 MHz radios or not but they have plenty in the 2.4/5 GHz (unlicensed) bands as well as the 3.65 GHz (licensed) bands that would probably serve your needs for cheap. Unfortunately, the 900 MHz band is getting quite crowded these days, leading to lots of interference and reduced "throughput".

Mimosa is another (younger) company making similar gear that's relatively cheap with good bang for the buck.

A place I do some work for has several 15-20 mile links (6/11 GHz) pushing ~500 Mbps although those are much more expensive.