Where to buy / sell your code?

Hi there,
I am in search for a website where you can buy / sell code. I may add that I do not mean to sell a side hustle or abandoned project but specifically custom code that has been developed (maybe as part of a side hustle) but is "too good to throw away" if you want. Could also be students that created something during a project and now want to sell it.

I am in a situation where I have basically a complete project with a ton of automation stuff going on (automated server provisioning and shutdown) and I would sell that part of the project, but not the project itself.

Thanks for your help :)