Love all my 301's...I have two black, one tan
My first was found where I live in NY at a tag sale at a Church. It was 30.00 and at that point didn't know what to look for but price was right. I found it was missing bobbin case and needed svc, that was before I knew how to do my own oil/grease etc...Cost me 275.00 in the end to get it up and running. Lesson learned make sure bobbin case there and svc yourself.
My second I found in RI listed in an ad Tan color in cabinet w/all attachments asking 150. I offered 100 they took it and it's my favorite since it's in the cabinet and has a knee control which I love. It had it's bobbin case...first thing I cked. Worked beautifully. Did all my own oil/grease.
My Third I found in an antique shop in CT hidden under a table in it's case. I opened had everything including a tag showing recent svc by a sewing machine co. Price 50...I knew it's worth and grabbed it. I use them all.
My Tan one came w/cams which work with the 301 to make all diff stitches.
So like all have said it just depends where you find one and what they are asking. Personally I feel if it's complete in case I'd be willing to pay up to 100, no more but I'm cheap...