Cost will vary on who/what system you get. I found the Ridetech E3 system and being a techno geek fell in love with its automatic leveling system. It has sensors mounted to the control arms so it monitors both the bag pressure as well as how far up/down it has moved so you can have preset ride heights that it goes to no matter if I have 400lbs on the passenger side or if its empty. Naturally this is more expensive then just a traditional set up like tony did with just some gauges/switches but both do the same job, short of the auto-leveling I mentioned. I have seen systems start around $1k I think but [MENTION=17070]Tony[/MENTION] would be better to ask as he has been playing with them for a while. The hardware on mine was $2k.
Are you wanting pics of the bags, the digital display or something in particular? My video is cheesy as heck but it gives you the idea.
[video=youtube;-ZTMA_wxwAM]http://www.youtube.com/watch?v=-ZTMA_wxwAM[/video]
I would not have made it into that garage with out the bags.