Hello. I'm a new user. I bought the software a few weeks ago and I just published a site.
The question is, how many sites can I publish and host with BSS? Is there a limit or can I just pay for domain externally and publish and unlimited amount of sites using BSS' free hosting?
see section 3 of https://bootstrapstudio.io/pages/license
You can buy domain names (or not) and export as many sites as you can generate to Bluehost, GoDaddy, Interserver ;) wherever.
But there is a limit per license for free hosting that's included in the licensing purchase as posted above.