This is the way to go, about $150 new and accurate.
Chuck from Elephant has positive things to say about it, and my experience mirrored his-we used this tool and then double checked it on scales and it was spot on.
Home alignment is another topic, but again with less than $100 in tools you can do it yourself, over and over.
Over the years with my track car I've had the suspension substantially apart for upgrades or repair about once a year. I can't afford to keep taking it to the shop.
http://forums.pelicanparts.com/showthread.php?t=308187&highlight=wheel+scale+jack