I have one of these....

http://www.ebay.com.au/itm/Pinball-Trolley-/281730397275?pt=LH_DefaultDomain_15&hash=item419870b45b

I wouldn't be without it.

That one listed for $560 is apx $360 overpriced.
A company up here was selling them for $199.
They are only good for lifting a machine slightly off the ground to do legs.
Any huge movement and the Jack collapses back on itself.

If you are going to spend money. The flat top red lifters from machinery house are the way to go.
Even Tony's (Ant68) pinball skates are a bargain and work perfectly.