I got a smoking deal on a "demo" Lincoln Square Wave 200 that wasn't even opened. Found it on marketplace. I was going to get the Miller 200 but they had a lot of problems with the board dying and it's an expensive fix, so I started looking around for the Lincoln.
It's not a cheap brand, but it's a reliable one and I'm very impressed with it. Keep your eyes open for deals, or used machines. I also got my MIG for 1/3 the price, but that was because Home Depot labeled the price wrong. I actually went in with the lowest price I could find online, to try and have them beat it by 10%, but I did way better than that.