I hate to be the bearer of bad news, but even in the best condition, it's not a real valuable machine (at least around here). It's a lovely machine, all metal and will last a lifetime for most any sewing needs. It's a little noisy, but other than that it's a good quality machine.
Unfortunately, t's not one that die-hard collectors are looking for. It's not old enough to attract the segment that love the really old ones. It's not unusual enough to attract those who want something odd or rare. The engineering and production is not fine enough for those who marvel at and collect innovative designs. It's not a "hot" model that everyone is looking for like the Featherweight.
Based on what happens here (North Texas), if you are willing to work it, you might get in the range of $100 to $150. for it. You would have to take great photos, write a good description, regularly re-post it on the sell sites (craigslist, offerup, etc.) so that it shows up toward the top and be willing to wait for the right buyer. I would ask $200. and hope to get $100.
Hopefully, I'm wrong. (It won't be the first time.) Maybe you'll find someone who's mom had a machine just like that and wants it for that reason.
bkay