As I mentioned in my first post, I spent $200 on mine, and the tune up is costing me $99. I fell into a deal though, so I wouldn't expect to get away that cheap. I've seen machines like mine go for as little as $700, and as much as $1500.
While mine is in the shop, I'm using a borrowed Brother home sewing machine just to get used to the idea of running it. It's teaching me to sew straight, and I'm about to start some curved pieces. I know controlling this thing is going to be nothing like the Juki, but it's giving me some insight as to how the whole sewing thing works.
Maybe I'm wrong here (Dan? Sniper?) but I don't see a thing wrong with learning the basic skills of material control on a small home machine if you can't afford to go out and buy an industrial machine. We'll see how much I've really learned when the Juki comes home and I get on it.