Price sounds way too high. I had a Trailblazer many years ago. Its an ok quad but compared to something like a Scrambler 400 2 stroke, its very underpowered. A Scrambler 500 would be better. Its basically the same size and you can get it with 4wd as well. Granted it is quite a bit heavier, the 500 will still blow it away on performance. A lot more power and the 500 4 stroke is just a much better engine than the 250 2 stroke. No need to buy 2 stroke oil either. I know Polaris has the automatic oiler but many times those fail and that is the cause of a lot of them needing to be rebuilt. They end up running the quad without oil and burn the engine up. For $1800, you should be able to find a Scrambler 500 in good condition. A trailblazer should be in the $800-$1000 range.
There are other choices out there for an auto quad in that price range though. Yamaha made the Kodiak 400 in a 2wd version that would be in the same price range. Might even be able to find a 4x4 version for a little more. I dislike the chain drive on all these Polaris models. The chain will slowly stretch over time and will need constant tightening or it will pop off when riding. Yamaha and also Arctic Cat as Hydrex mentioned have shaft drive which requires zero maintenance and gives you more ground clearance too. You can find good deals on old Arctic Cat models as well. They would be utility machines but did come in cvt auto so would still be good for a beginner. The 400 did come in an auto, as well as a 500 in auto as well.
Honda has the ES utility 250cc Recon which is a good beginner quad. Its not fully auto but the push button electric shifting is almost as easy and makes better use of its 250cc. It still tops out at around 48-50 mph, plenty fast enough for a beginner. Its also much smaller and lighter than any of the Polaris models, making it easier to handle and more manuverable on the trail. You get racks front and rear so it can be used to do some work if you want or just haul a cooler if you get thirsty out riding. You should be able to find one of those in the $1500 range in good shape like this one http://evansville.craigslist.org/snw/5873333578.html