When moving house in mid-2020 my wife and I had a mass clear out of all the junk we had acquired over the years. To our surprise it was very easy to sell online. The best items were books: easy to post, not fragile and retaining value. After the move, sensing there was a boom in reading during lockdowns, I expanded the operation. I bought overstocked books from wholesalers and sold them online. As with all enterprise these days it turned into a data analysis project. For more details please see the links below.
Details of the project and some analysis and tools deployed on Heroku
Some basic analysis of the selection process, pretty visualizations and thoughts about how to improve stock selection.
a nice summary of the data from the notebook
The GitHub repo fro the app deployed on Heroku: