I heard that typically it's around 800 - 1000. Is it true?
What about VPS? How many users usually share a VPS?
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.
On shared hosting there is no typical, consider a server a pie.
On a shared host, they cut the pie into as many pieces as possible as limited by hardware and acceptable latency (to the average user). The pie is the same pie for everyone. (Everyone shares memory, disk, etc to an extent)
On a VPS, you're given the whole pie to yourself, you have control over it. The size of your pie is determined by how it's provisioned. (You're guaranteed X MB of RAM, X GB of storage, that is not shared with anyone else).