Ok- if this is the ORIGINAL style in off white, in very good condition with a case that is in good condition (and does not stink) with attachments . . .
Then it's not a bad deal. The "tan" are much rarer than the "white/celery" newer style, so don't be confused by that. It would be a high price for a newer style white one (with white/green case).
Make sure you get the tan footpedal - that is part of what makes this older one so neat.
BTW - in general, the white/celery ones can be bought for less than the black ones, which can be bought for less than the "tan" ones, which can be bought for less than the open arm (222) ones.
There are always exceptions - depends on how lucky you are. I found two white ones this last summer - the sellers didn't realize the FW came in that color - just thought they were cute little sewing machines.