Consider what you can afford to lose if it doesn't work.

Yes there's a risk, but I have found that the behavior of the seller is usually a good indicator of what you may be getting yourself into regarding the item when one has an opportunity to do so on CL. For example, my SS Kitchenaid fridge was several yrs. old when purchased and was part of a divorce settlement. The seller was respectful in her dealings with me and her story appeared consistent with my onsite visit. The fridge has worked like a charm for the past two years after purchase. Also, I sold my perfectly good appliances on CL as they were the wrong color for my remodel. I made certain the appliances were sparkling clean and had a well written CL ad. The purchasers were all immediately impressed with what they found. Anyway, resell has worked well for me, both as a buyer and a seller.

Calizzy:

In addition to the considerations offered by others, here are some questions/suggestions for you to consider.

Are you looking at gas or electric ranges?

Gas ranges tend to be somewhat more durable. IIRC, the most recent appliance life study for Consumer Reports showed gas ranges lasting about 13 years on average and electric ones a couple of years less. There seems to have been something of a drop off in reliability and durability of stoves made, say, five years ago. Judging from what I've read here, a lot of the problems have been with electronics. CR's latest report on "repair or replace" indicates that most appliance manufacturers have made efforts to upgrade durability and reliability.

First, how old is that "nice-looking" Kitchenaid range? KA ranges and wall ovens models (and some sold under the brand of corporate parent, Whirlpool, too) models from roughly 2008 to 2011 had some pretty well reported problems with the oven self-cleaning functions. Sometimes, using self-cleaning would toast the electronics, sometimes it would trip a thermal overtemp breaker that could be reset but only by after disassembling the range or oven. Many stoves were okay, but there were a pretty fair number of reports here which you can find if you search on "gardenweb + kitchenaid + self-cleaning."

Another point to consider: the data from Consumer Reports' annual membership surveys have shown that Kitchenaid gas ranges are the least reliable brand of gas stoves followed by Maytag. Both Maytag and Kitchenaid are Whirlpool brands but, oddly, gas stoves sold under the Whirlpool brand have been significantly more reliable.

For electric ranges, the least reliable brands have been Kitchenaid, JennAir (also a Whirlpool brand) and LG. According to CR's most recent report on product brand reliability, there aren't statistically significant reliability differences between most other brands of gas stoves but GE-made electric stoves (which include Hotpoint and some Kenmore models) are the most reliable electric ranges.

Next question: do you need to buy a new stove right away? The prices of used stoves do not seem to vary much, but when the major holiday sales weekends come around, new ones can be a whole lot less expensive. An $800 budget may go further then than it would if you needed to buy a stove this week. For example, if you can wait to the President's Day weekend in February, you may find your budget goes further with some stoves you may be considering.

I would take a nice old gas range over a new cheapie any day!
We have a 1969 Kenmore range that came with our vacation place, and it works like a champ!

Agree with what JW said.
We have bought appliances at auctions but the amount you pay has to reflect the risk you are taking. We have paid no more than $5-25 for working appliances. You also have to have knowledge about what you are buying. Can you make repairs or would you have to pay someone to do it? Some are simpler to repair than others. Perfectly honest people with good intentions may sell a range that doesn't bake well but since they never bake, they don't know it. Even moving an appliance can adversely affect it. This can happen even with new appliances but you have a warranty to back it up.

I see we overlooked calizzy's question: "what about dishwashers?"

What about them, indeed.

Do you have a budget in mind?

Buying used is taking the chances that wekick has outlined. Sometimes, it works out well and lasts a long time. Sometimes not. It really helps if you can do DIY repairs.

For example, when I moved into my house 17 years ago, I bought a used GE dishwasher as a stopgap, When I got to the kitchen remodel four years later, I bought a new DW and sold the GE to a friend who is still using it and has never had to do any work on it.

The replacement was a Bosch that lasted 12 years. The controller circuit board burned out. The part was no longer available (at least, it was not avialable any place I checked.) This happened on a holiday weekend with big sales. With the sales pricing that weekend, I got a new Bosch at a 40% discount, a price that was roughly $100 more than the prices for recent model used Bosch DWs on the Craigslist for my area. My concern with buying used DWs from an auction or from Craigslist or newspaper classified ads is that it is hard to know the history and hard to know anything about the sellers. I am more comfortable buying from a reputable dealer such as the the Habitat for Humanity "Re-Stores." There are two in my area, and both had good used DWs though all were older-model and low-end GEs, Whirlpools, Maytages and Frigidaires with heating coils and grinders. My personal preference is for condenser style drying (no worries about plastic) and filter drains rather than grinders (I once had to pick shards of glass out of a grinder). The models were older than the ones on CL that weekend, and so the prices were a bit lower. I decided that I preferred a new DW with a warranty and features I preferred over saving some up-front money. Had my budget had been tighter, I might well have chosen differently, bearing in mind the points that Wekick made.

As for buying new, it seems that even low-end DW models (mostly) do a good job of cleaning dishes, at least according to the product testing by Consumer Reports. (Get a copy of the appliances edition to find the ones you want to avoid). The difference between inexpensive and more expensive is usually a matter of:

(a) how long it takes to wash (inexpensive ones may take up to three hours for a load, while mid price ones like my Bosch SHE55M will do a heavy load in 95 minutes, a light load in 30 minutes);

(b) how quiet the DW will be when running;

(c) whether the tub interior is stainless steel or synthetic/plastic (a functional matter for condensing drying types, more an appearance/durability matter for those that use heating coils.

(d) extra features (kinds of cycles, rack designs, number of racks, built-in water softeners, etc.)

CR's January 2014 article on repairing versus replacing indicates that the DW brands with the best durability and reliability are Bosch, Miele and Whirlpool. The least durable and reliable DW brands have been LG and Samsung. CR's survey results suggest that dishwashers may last for a decade or more but about 20% of them will need repairs in the meantime and it is generally more economical to replace a dishwasher that fails in year 6 or later.

Hope this info helps.

Don't discount the warranty. Even new appliances break. Nearly every one of my kitchen appliances has required service within the first 2 years, including recently installed Miele d/w replacing busted Bosch. The comportment of a CL seller can help you screen for someone deliberately unloading a lemon, _maybe_, but not for the mfg. defect that hasn't triggered. Agree w/ Wekick. If you can install & repair yourself this may be a risk-reward trade off, but don't neglect warranty value.

Your budget will allow you to get a very nice range. I replaced my ancient range with a Frigidaire Gallery Convection Range. Consumer Reports rates this up there with the Samsungs and other high end convection ranges. I do agree that you can get great appliances used as some people get rid of perfect appliances for remodeling reasons.

Just as reference, late model GE, Frigidaire, Whirlpool gas ranges that are in good, working condition are about $200 in out local area.

We found a model of Whirlpool - gas slide-in, brand new in-carton, with larger burner btus, delivery included, warranty, convection oven with real self-cleaning and some other features for $800 at our local Lowes during the last round of appliance sales. Currently, they have 41 models of dishwashers available under $400 with a few under $200.