I bought a 650lb capacity lift table from Grizzly at one of the scratch-n-dent sales for 100 bucks. It looked brand new, but would not lift. I figured it shouldn't be too hard to figure out what was wrong with the jacking mechanism. It was full of oil, but would not lift. Turns out the inlet check valve to the pump was stuck. Once that was freed up, it worked beautifully. I use it for moving heavy stuff on and off the trucks, it gets used as an adjustable height workbench, and got used a lot as a miter saw stand. Also comes in handy as an extra crash cart for working on vehicles, the adjustable height and locking wheels make it perfect for that use. I didn't think I'd have a use for one, but at that price, I figured it would be worth a try to fix it and flip it if I didn't use it. Well, as it turned out, my lower back disintegrated and I've needed just about every bit of help moving stuff as I could come up with.
Highly recommended.