Limit products or categories

is there some way to limit the amount of products?

for example, to limit number of product to 100 amount, thus if a user tries to place more of 100 product the system shows an error, that is possible ???

There is an add-on for Minimum Order that could probably be adapted for this ...

Thank you for your response. I will check that out.

I think i explained that wrong, it was not what i was looking for, what im trying to do is i have customers that want an ecommerce software but they are only willing to pay so much. So i seen so places where they limit the number of products they can add to a store so that way i can charge by the piece. so i should not say limit categories just the number of products.

So i was wondering is there away to encrypt the software or limit the amount of products they would sell in there store.