There are many reasons why people buy things and then change their minds.
First, when I decided a few yrs ago that I wanted an emb machine I searched eBay until I found the Viking #1 and got it for 600, which included all attachments and a 2 yr warranty. I got it and was so excited, it kept breaking the thread. At first I thought it was the pressure plate because it had lots of nicks, the seller sent me a new one, that didn't fix it. So he paid for me to send it back to him for repair. In the mean time at my LQS, one of the workers bought a Viking Ruby, used it 7 hrs and decided she wanted the newest one that had came out. I got such a deal on her "used" machine that I got it. By the time I got the #1 back from being serviced I never used it because of the Ruby, which I traded in for an equally great deal a yr later for the latest model. So now, eventually I'll get around to selling my #1, which has been serviced and has all orginal attachments plus a few extra.
Then a few months ago I was in the same LQS and they had just moved and found a few machines that had been demos and forgotten about for sale. One of them was their next to latest serger, Huskylock 21, the price was cheaper than a cheap on at Walmarts, I couldn't believe it. I'd been wanting one so I got it. A month later I was at a serger event to learn some new things and fell in love with the latest Ovation by Brother. Knowing that I can sell the Huskylock easily for the price I paid I got the Ovation and have already in the first month taken 2 classes on it. Both my emb machine and my serger will be well used and I'll sell my other two that are great machines, the serger has full warranty on it. It's not that I have a lot of money, definitely not but I got great deals and I've kept my promise to my self and I use them both alot.
If you find a machine, then go and try them out. Some times those lines, never used or barely used are true for simple good reasons.