Sharon, it's a really NICE 15-91 in a super cabinet and bench. Love mine!! John is right, $150 is a bit steep, and you'd have to replace the spool pin, which should be no problem....
You absolutely should try the machine, take a scrap of fabric (preferably a solid so you can see stitches easily) and it looks like you'd need a thread stand as well if you have one. If not, wing it...but try it out. Check the wiring. (It looks to be in fairly decent shape in the pics).
Don't forget that if the tension is off a bit, the lack of a spool pin (EASY find, I think I might have one for you) the machine needs oil, etc., are all easy fixes...but you can use them to bargain with.
Give them an apologetic look, tell them that you don't mean to insult them, but would they consider $50 or $75 since you will have some work to do on it before you can sew. See what happens, and let us know if you need a spool pin!
