There are many available in the different price ranges. Some important things to look for is the size (length) of the lift pads and the bolts used in assembly. Some use grade 3 bolts which I don't think are a good choice being it will be holding 500-800 lbs of a bike on them. You can always upgrade the bolts with grade 8 which is a good safety idea if you buy the cheaper lifts.
The pads range in length from 14" to 17" and I like the longer ones on a quality lift over the short ones that would barely make it under the frame of a bike from side to side for obvious reasons.
Here's a list of the lifts available to shop from. Some have had problems with the sears lifts with the jack going bad.
Bike Lifts - Harley Davidson Community