Is the HP-75c valuable at all?

[d b]

The price on ebaby is usually the going price, just be definition.
Make sure you spelled Hewlett right and have all the dog whistle words included for searches like calculator (even though it isn't), programmable, card reader, works (your dad tested it for you, right?) and mention the manual if you have one. Include a good close up of the screen because when those go they are gone, and another close up of the battery compartment & mention any flaws. Folks don't mind cleaning up battery burp but don't want to be surprised. There used to be a difference between, for instance, HP75C and HP-75C. A long time ago, I think Mike D said the hyphen covered both but the unhyphenated wouldn't call up the other, so use them both somewhere just to make sure.

About the price; there was a glut in the market about 14 years ago when a bunch of these were sold for $3 per. The price has probably risen a little bit. I found one at the local flea a of year later for $6. I figured I saved on the shipping so I treated myself to a tostada de cebiche.

Have you considered buying it from him and then getting him to show you how to use it? If you do any kind of engineering, having one of these on your desk is a real conversation starter with the old timers (that's most of us here).