I agree with everyone else, it really depends on the market where you are living. My local Brother dealer said when they have someone wanting to trade in a machine they check eBay to see what they are going for. Good luck

I recently bought one for $9.99 at a thrift store in Minnesota while traveling in a case similar to yours. Excellent condition and runs great.

This is a 401A and I bought mine in June 1959. The fourth photo shows the machine from the back. Notice the plug on the left side near the bottom -- well, it is not placed in the machine correctly positioned. If it were placed accurately, there is not a problem. The bottom cover can be removed and my 401A sits in what looks like a card table. I bought the card table when I bought my 401A because I did not know what style of furniture I would want. The Singer store sold the card table with the 401A and I don't remember the price. Singer also sold a matching folding chair. In hind sight I wish I had bought four chairs with the card table and the 401A. I have the case, manual, all of the cams and the optional feet and both stitch plates (straight stitch and zigzag).

What machines are listed for on Ebay is not necessarily what they sell for. I bought my 401a in the Chopenhagen cabinet with stool and the complete accessories box and manual from the original owner for $60. I was happy with the purchase and the machine is great.

I paid $75 for mine with the table for it. Sews great.

I love my 401A, purchased in 1958. She has sewn a multitude of projects and is my go-to machine. I have made seat covers for a VW bug, draperies, etc., etc. My DGD is salivating at the thought of inheriting it.

I have several of these machines and have sold two. This machine is said to be one of the best Singer machines ever
built along with the 500. It is all metal gears, direct gear motor drive, and a slant needle. It is tough and will sew
through anything.

Once they are cleaned up and adjusted you can fetch up to $300.00 for one. I sold both of mine for over $150.00
without the case. An original case in as good of shape as this one can add $90 to $100.00. An original plastic
attachment case and book can add another $50.00.

Craigslist is a poor place to sell good machines. Etsy is a better online site and you get a truer value for your machine.
A better place is in person at bazaars, home-shows, quilt functions, and local adds. You can sometimes buy them cheap but by the time you clean them up and add the case, book, and attachments there is a lot of value in the machine.

People who know the 401, 403, 500, and 503 appreciate them.