The short answer is it's worth whatever someone is willing to pay for it. Now here's the long answer - What condition it's in, whether it's been serviced recently, case or cabinet, whether the manual and accessories are with it, what part of the country, how rare the model is(most aren't), what color it is, how bad the seller really wants to sell it, what day of the week it is, what phase the moon is in, depends on who you ask, etc...all can be part of determining what a sewing machine is worth. Only you can decide how much you're willing to spend.

Cari

Follow up and Cari's value comment.

Level of advertising is a huge factor too. Last weekend I went chasing a Rocketeer. CL listing under garage sale. "sewing machine" was the second fuzzy picture. Nothing to even indicate Singer unless you were a fan. It was in a town of 300. 15 miles away from the nearest stoplight. And the actual sale was a "make an offer" sale at a motorcycle shop. Seller didn't know what he had. All factors in my favor. I made an offer for the 500 in a cabinet with manuals and two sets of cams. He upped my offer by $5.00. Bingo.. oh wait. my GF was faster with her money. Giggle. I won't tell you the purchase price, but it would make many of you groan. Someday I'll have to get a pic of her 500 by my 503.

Leon

Edison Machine
 

I have this machine but it is called Edison. Mine doesn't have the crown on the bed but the rest looks the same! I am trying to find out info on it, don't have the book. I think my mom bought it in 1959 but not sure. Would love to have more info. Any help appreciated.[ATTACH=CONFIG]573991[/ATTACH][ATTACH=CONFIG]573992[/ATTACH]

Somewhere on this thread is a generic manual.
I made screen shots of your machine controls. So I'll explain them the rest will be generic and you can find that information by reading the thread.
[ATTACH=CONFIG]574002[/ATTACH]
This is your zig zag control. You turn the big knob to zig zag what ever you want and can change it as you sew by turning the knob to larger or smaller stitches as you sew to get different designs or appliqué or fancy calligraphy lettering. If you want to lock it in place slide one of the two little lever knobs where ever you want the stitches set and tighten the knob. You have to release them in order to go back to straight sewing or to change the width of the zig zag stitches. Right now it looks like it might be set so turn the nut on the ends of the two lever knobs and release the zig zag so it will sew straight again. Pretty simple once you play with it a minute. If you want to reset it, turn the knob how ever wide you want, set the levers, tighten and you are back to zig zag. Release them etc. pretty simple and straight forward.

[ATTACH=CONFIG]574003[/ATTACH]
Stitch length. Turn knob to change the stitch length. R is reverse. Pretty straight forward.
Below is two buttons. Push the one that says up to sew anything. The down button is for free motion sewing or darning and the feed dogs will not be activated.

Your generic manual will show you how to thread it and how to use the bobbin.

Have a thing for the vintage Japanese made machines. Will try and figure out how to post pics. Thanks for yours Miriam!

Thanks. The icon with the tree gets you to the picture place.

I got a machine yesterday just like this one but it is badged Sew Vac. It is also a JA-33, J-C5, UE81, KK, model 750 with serial number 09813. Same pretty blue color. I am trying to identify what japanese factory made it and what company badges sew vac. I think our machines are cousins!

Copy of manuel
 

I have the same sewing machine and your right , Ive had trouble finding any info on this machine beside a picture as a tease .. I have model 88 and cannot find the Manuel , but blessed to have seen yours. It just about identical.
Esmeralda

Can anyone please offer any information on this incredible machine? It's my Mom's and she's had it since the early 1970s. The tag says Kingston by Brother. I can't find a model number on it anywhere. Any help is appreciated, thanks![ATTACH=CONFIG]582378[/ATTACH][ATTACH=CONFIG]582379[/ATTACH]