I bought my Floor Jack at Sam's Club, same owners as Walmart, for around $100. It's a Indy5 by Allied International and is ASME and ANSI approved. At the down position it's only 5" high and it has a lift of 20". The lifting handle also opens and closes the hydraulic valve is 48" long and is permanently attached. It fits under my 1980.
Forgot to state it has a 2 1/4 Ton (4,500lb) lift capacity.
A lot of floor jacks should fit under the frame that you can get from AutoZone, Sam's, NAPA, ..etc. I also spent $30 at a local metal fab shop to have a custom plate made out of 3/8" steel that replaces the round jack plate to mount up perfectly with the side frame rail and keep it from (potentially) slipping off. I can still put the round plate back on when necessary.
Check out Sears. I got their "SUV" jack and stands. I got 4 three (3) ton jack stands and a 3 ton jack for $89.00. The nice thing about getting the SUV style, they'll lift the car up so high your neighbor will think you put in a lift system.