Can I run more then 1 instance of scrapebox without buying another liscense?

Yes. You can run multiple instances of scrapebox with one license, however all instances must be run from the same physical machine.

Each instance must be run from a separate folder.

For instance create a second empty folder:

/scrapebox/
/scrapebox2/

Then copy the contents from your original scrapebox folder to the second folder so you have two separate copies.