Install same plugin more than once on same wordpress website?

You can’t.

I recommend asking at https://www.ads-software.com/support/plugin/3dpc-quote-calculator-basic so the plugin’s developers and support community can help you with what you’re trying to accomplish.

Is it possible to install any plugin more than once on the same website?
If I created a custom plugin then would I be able to have multiple stores?

No.

But each instance of a widget could have different settings.

What do you mean each instance of a widget could have different settings? Would it be possible to have a plugin made into a widget?

Plugins can create widgets. Please — contact the developer of that plugin as I mentioned above to explain to them what you’re trying to accomplish.

Thank You. If I made a custom plugin would it be possible to turn the plugin into a widget?

No, but the plugin can have various widgets each independent of one another-

Do I make the widgets or does the plugin have to have them?

I don’t think you understand how WordPress actually works, what plugins do, or what a widget really is. If you are a developer, start reading here: https://developer.www.ads-software.com/