I have two of these. One was natural gas that I have since converted to propane, and I paid $150 in very good condition with a ok condition cover. Converting was not dificult but the tank holder is not available from Weber any longer. I had to get creative when ordering the conversion parts, and have more of a investment than I prefer.
The second one I found a few months later and had all the propane parts and a cover. It is in very good condition also and I paid $75.
They do not come up for sale often in this area. I have only seen one other in the last several years.
They don't put out a great deal of heat and are pretty noisy because of the propane flow through the regulator and orface. The flame looks natural though and as far as how much propane they use, I can't really say because I haven't used mine that much. I'm sure it's significant.
Make sure the logs aren't broken and there isn't a lot of rust in the bottom near the burners. It is flat there and water tends to just lay in there. There should be three metal shields to in close the fire box when not in use. Make sure you get those! A cover would be a plus, but I think covers are still available from Weber.
They are nice to sit around if its not to cold and really look cool while burning. Hope this helps. Good luck.