How can I offer specific products for free to certain customers?

[Recycaball]

I’d like to be able to offer some products on my store for free, but only to certain customers.

I’d like to invite people to register for an account, but that process needs to be validated manually rather than automatically.

once they have an account, I’d like to be able to offer them some products for free, however I’d like to stock control them. For example I might only want customer A to be able to order one item, but customer B can order 3.. etc 

is that possible?