A: Hello

Users are unlimited.

Code is like a gift voucher. You buy code on AppSumo and "redeem" in Neuron.
Depending on how many codes you redeem, you get different plans, as described.

Quote...
"" All future Bronze (1 code), Silver (2 codes), Gold (3 codes), Platinum (4 codes) or Diamond (codes 5-7) Plan updates ""

Hope this helps