There are generaly no issues when purchasing a used stair lift, however you should check the mechanics of the lift to make sure it's functinoning properly.
Like many other second-hand items, purchasing a used stair lift will be much more inexpensive than purchasing one brand new. Also, the previous owners may be a good source of information about the quality of the product.
Health insurance will cover a portion of the purchase and installation costs, but you're on your own for maintenance costs.
Here's a place where you can buy a stair lift: http://www.usmedicalsupplies.com/Stair-Lifts.htm
The weight capacity of a stair lift varies for each stair lift. Average capacity is between 250-300 pounds.
It is better to install a handicapped stair lift.
One will need a pulley to install a stair lift as well as many other tools. A screwdriver, hammer, and perhaps even a stair lift kit would also be helpful in installing a stair lift.
The prices for stair lifts range from $1200 to $4000. The average price spent by most consumers is around $2000. This, of course, will vary depending on the type of stairs that you have. The average prices are based on straight staircases. Here is the link to a great article at stair lifts and their costs that you can take a look at: http://www.articlesbase.com/elderly-care-articles/stair-lift-price-how-much-does-stair-lifts-cost-1009388.html
You can get a stair lift installed in your home for around $1400. Of course this price could vary depending on your needs.
If you are looking to purchace a minivator stair lift you should expect to pay anywhere from $700-$3,000. The average price varies on the type of stair lift you select and on the features you desire. Their are websites that sell used or fairly used stair lifts at a lower cost.
There are many websites where one can buy a straight stair lift. Among them are Bruno, US Medical Supply, Active Forever, EZ Able, eBay, Stair Lift Exchange, and US Medical Supplies.
Some popular stair lift manufacturers include SilverCross, Savaria, Bruno, AmeriGlide, and Precision Stair Lifts. Stair lifts can vary in price from $1289.99 to $2299.99. If you're looking to get a comparison on the different brands of stair lifts just google "Silver Cross Stair Lifts"