Do small civilian aircraft have autopilots?
Many small, light aircraft are equipped with an autopilot today. They can range from very simple autopilots, without altitude selector and so on,



Source, ST SYS 30, $ 12,000



to advanced systems with altitude selector, automatic trim and so on.



Source, Bendix/King KFC 225, $ 15,000 - 42,000



And with this GPS, feeding the autopilot with data, it has the abilities of an airliner.



Source, Garmin® GTN™ 750, $ 17,000



You have to know, the systems in the general aviation industry are getting better and better. Of course they are way below the complexity of the avionics of airliners, but the features are the same if not more. 

For example: A captain of an airliner has to review or change the flight plan with the FMC, respectively MCDU on Airbus, a not very straight-forward device to control the plane.

Of course, the FMS has a lot more capabilities than a GA GPS, but one of it's primary features is the input of the flight plan. And in that, from the usability-view, the Garmin® GPS has the better solution: An all-in-one navigation device with touchscreen input.