Rotary and Bendpak are 2 brands I am familiar with. I have Rotary lifts in my shop. I have 2 post lifts, but they also make 4 post lifts. Depending on your application, 2 post lifts are usually cheaper, but don't give you the convenience of drive on. With 2 post, you also have to consider how low the vehicle your lifting is to ensure that the arms are low enough. Rotary is the brand that most of the shops in my area seem to have. I have had no problems with mine.
As far as capacity, it really just depends on what you are going to be lifting. 7-9k lifts are plenty for cars and pick-up trucks. As for pricing, the cheapest I have seen a 4 post new is around $3500 and that's a light duty unit. However, you may be able to pick one up used for less. If you decide you could go with a 2 post, I have seen those used in the past for $1500-2000. Keep in mind that with either 2 or 4, they usually have minimum requirements for the floors that they are bolted down to. You'll also need to consider wiring and electrical requirements.
Hope this helps at least a little bit.
