If you are pulling a camper with it, then airbags would be the route to go. I have looked into several different systems, by the time you get an on-board compressor and tank, you will have spent $500 or more. The bags themselves are fairly reasonable, if you don't mind having to find an air compressor to fill them up.

They have automatic leveling systems now that I have heard excellent reviews about. The price on some of the automatic systems are cheaper then some of the manual systems, because of the reduce amount of equipment.

 

Just bought a Air Lift system ($175 shipped to my door)
Bags only, no problem finding air to adjust.

 

Just grab an air tank from harbor freight or notrhern or somewhere else cheap and throw it in the truck to make adjustments. Also handy if an ATV has a flat in the middle of the woods.

 

Just an FYI.
I had a wal-mart cheap-o 12v cigarette lighter compressor, you know the ones that say Heavy Duty Truck Compressor 500 PSI!!!
The darned thing actually had enough wire to get to the tailgate. BUT.... the resistance is so great it heats up at the plug and melts the wires out of the plug.

Then I got the Airlift compressor and guage kit. This was more than 5 years ago and it looks like the ones now are better. It was better but you had to hold the button for a while. And the little guy will not fill a tire without burning up.

Don't get me wrong I love my bags I'm just a hard guy to please.

So I got a Viair. A 200.00 pump but it's me for sure.

So without going overboard like me one can run some nice wire to the rear for a cheap-o hand held pump to do the job pronto. I'm sure there are better units than the crap-ola I got from Wally world.

 

i put the schrader valves for my bags behind the gas filler door, and i use a cheap harbor freight air compressor that plugs in my cig lighter.

 

Which one you use air lift or slam air? you mount front axle or rear axle?

 

they are air lift slamair bags and the kit is #59209, they are for lowered apps. from 2 - 7 inches lowered heres the pdf on how they're mounted. 231.88 on summit.
http://airlift.iwebcat.com/imgVD/AIL/MN-682_59209.pdf