A good kit can be $2000, Depending on brand. An Air Ride Teck kit for a civic lists at $799 front, $799 rear, plus installation.
With air ride you get what you pay for, If you dont wanna be stranded w/ a prob, buy a nice kit, or get used to winding up/down coilovers.
Year One and Godfathers both are AirRide technologies dealers btw,
GC