Air bag kit is less than $300 with no compressor. Summo springs are over $500 - quite a bit more (both SDTruck prices for F350). Timbrens are a bit over $200.
The compressor kit adds $200 - 300 but is really a luxury. Generally you fill them up when you put the camper on, then check the pressure every month or so. You don't need the compressor with the rubber springs, but then you can't adjust anything either. With rubber springs there is no way to level the truck with and without the camper. Like steel springs, they require sag to work.
