Lifts normally include a drive-on ramp and a vise to lock the front wheel. If the vise is an option, I strongly recommend buying it. I've seen bikes fall off lifts, and it ain't pretty-or cheap. Other options include things like extendable sides, which are great if you're working on ATVs, snowmobiles or lawn tractors (and a way to sell the idea to the wife), and dropout panels that make removing the rear wheel a lot easier. Low-profile jacks are also helpful; with one end of the bike clamped to the lift, these jacks can raise and lower the free end incrementally, which makes tire changing or suspension work much easier.
As with any tool lift prices vary greatly; expect to pay anywhere from $1,000 to maybe $2,500 for one from the premium suppliers, such as Handy or Carlson. Their lifts are top of the line and won't let you down (no pun intended)-these are the ones I'd recommend if you're serious about working on your bike.
Cheaper lifts can be had too, and while I've had no practical experience with them, guys that have purchased them from places like Tractor Supply Co. (Clarke Tools) and the suppliers doing business on the 'Net tell me they're happy with them. Expect to shell out anywhere from $500-$1,000 for these, plus shipping.