Are the 99K machines of any value? I think mine was made about late 50's. It is in a cabinet. I don't ever sew on it but it is cute.

I understand the cabinet is worth more than the machine! I think the machine is pretty cooland certainly have value! I know cuz I have one in the cabinet too :)

They're not like the FW machines. I have one I bought for $10 at a garage sale. Had to clean it up and replace the belt, but she sews a pretty stitch. Mine doesn't have a cabinet. If the cabinet is in good shape, it is worth a lot more. And yes, they are cute!

I understand the cabinet is worth more than the machine! I think the machine is pretty cooland certainly have value! I know cuz I have one in the cabinet too :)

i bought one at a yard sale for $10 that needed a belt and a bobbin plate. the cabinet was in good shape. it stitches well and i like it but i don't think they have too much value. they're too common.

Value for resale? or value as a sewing machine. For resale, check completed listings on ebay.
As a sewing machine, they are terrific. They sew as well as a featherweight, and there are all kind of attachments for it that are reasonably priced. I do all my piecing on one, and it is so easy and uncomplicated to use, clean and oil. Hang on to it and use it. You won't regret it. (Unless you need to carry a machine around and need something lightweight, I think Featherweight's are highly overrated...and overpriced.)
As for them being common, so are featherweights, the most common sewing machine on ebay--and the highest priced, due to popularity and ....hype.

see above

I also got a 99 for 10.00 and it's awesome, dosn't have a case but love it.