$20, get the machine.
It weighs 44 pounds. That is less than fifty cents a pound. ;-) fits my criteria!
Bring an old lady cart. You live in a city, you have an old lady cart. ;-) you can do it. People on the subway always chip in and help if you need.
He is pulling your leg about having it serviced. He appears to know nothing. But for $20, we'll get it working.
The needles are round shank.
The timing belt is seen as you look under the machine; it is the main drive belt, and it is cloth with metal ladder-like ridges. It is just that it can be destroyed if it gets oil on it.
Really, get it. You will -not- regret it. If it is not working, it is probably a simple thread jam or re-wiring. Even if you need a whole new motor, that is easy, and this will be a great machine. If you go to see it and the handwheel does not turn, get it anyhow - though you could use that to bargain him down further if you wish... You can un-jam it and everything. I will help you, as well there are so many clever folk here.
Get it get it get it, now, y'hear? ;-) go girl.