intoquilting

I have a singer 306W sewing machine in a case. I was wondering if anyone knew what it might be worth. I haven't tried to sew with it yet. The case is a little beat up but still useable. It has some of the cams with it. The foot control looks like it would interchange with the featherweight and singer 301. Any information would be appreciated. I need to downsize some of the machines that I own.

WIChix

Value is in the eye of the beholder.
You may want to search for listings on FB Marketplace, Craigslist, eBay and the like. Keep in mind that listed price and selling price can be very different. FWIW, I bought my 306 for $20. It had no case, no bits, no manual. Just a cord and pedal.
When you list it, share the machine information: date of mfg, steel gears, aluminum body, needle and bobbin requirements, manual (even if it is a pdf), etc. Good, clear photos. Front, back, bits (not all jumbled up), etc.

Heresolong

I picked one up in a nice cabinet about two weeks ago for $20. Unfortunately for sellers vintage sewing machines aren't generally worth much. Better than making money, however, is finding someone who wants to learn to sew but can't afford (or shouldn't consider wasting their money) on a fancy new machine when these old machines will do almost everything anyone might ever want to do.