Some of them are two spool machines and are pretty neat. If it's a two spool make sure it has the spool can in it. It's like a big bobbin case where you can load a small spool of thread in it instead of a bobbin. The can alone can cost as much as the machine.
As a side note: I'm sewing a quilt right now on Ella. If you want to see the story check out "9 Patch on it's Way" here in the vintage section.
Rodney