Buying a used electric kiln can be a bit tricky so here are some guide lines to get you started getting a used kiln and getting it home.
Get some opinions and research a bit
There are some weird kilns that come up for auction some of them are from companies that no longer exist or make replacement parts it a good idea to check to availability and maybe see if you can find an online manual.
Get the model number,(this will help see if there are part available) find out the power needs- having to get an plug installed just for the kiln can run upwards of 400$ make sure you have room for it, sure I want a 24 cubic foot kiln, but it is a bit big.
ask the experts, see what professional potters have to say about the kiln , are the well constructed? do the heat efficiently? do that like them? there are a multitude of forums and potters are usually glad to help
Get some pictures
A good picture really is worth a thousand works. you want to find a kiln the looks clean, free of dirty, crud, chips, rust and water stains.
Ask get a shot of the interior; the brick should be free of stains and large breaks the elements should all be in channels and un-kinked if there is a kiln sitter it should not be bent or the tube it is in broken, pay close attention to the lip if the kiln, it should be smooth this is one of the places that can take a lot of damage if one is not careful and a damaged lip really cuts down on a kiln firing efficiency. The control box; it should be free of rust melting, and staining these could mean wiring that need to be replaced or in a computerised kiln it could be a computer that doesn't work right. the outside of the kiln should look well kept, not large dents or gashes these could indicate damage to the brick inside.
Get some history
Find out what this kiln has been used for, how often, how long. an electric kiln that been used for salt firing may not have long to live and may ruin future glaze and bisk firing as salt and chemicals gas out of the brick. Also element exposed to salt need to be replace frequently. a five year old kiln owned by someone for a hobby firing low fire that was barely used will probably need a lot less work then the one year old kiln owned by the studio potter firing high fire.
Find out where the kiln was keep or stored, for example stored outside unprotected can take a lot of damage
Find out why there getting rid of it, this may seem pretty basic but its a good idea especially if there a 'need some work note' in there. ask what work in needs, replacing an element is easy(if you know what your doing, if not get a professional playing with electricity is BAD) were a replacing fire brick is hard, and expensive in both time and materials.
Getting your Kiln Home
Kilns don't usually ship so take travel and how your going to move the kiln into consideration when bidding. A kiln in Texas may sound like a good deal but then you have to drive 500 mile in a rented u-haul it can really add up.
Kiln don't like to be jostled, fire brick is delicate and a pain to replace. make sure the kiln pieces arn't going to move or rub against anything, Its a good idea to bring some blanket to protect the pieces if you are moving a kiln the comes apart into rings like a scutt. Dont stack anything on top the the kiln or leave anything lose by the kiln that could bump into it.
Kilns are big and delicate even though they don't weight as much as many people expect, so bring a friend or make sure you have someone there to help you load.
Well i hope this helped and happy firing