Discount scenario need help

i want to have 20 products with price 0 for registers customers only

so i go to discounts and create one

discount type  = assigned to products
use percentage 100%
discount limitation = N times per customer
N times = 1
max discount quantity = 1

requirement tab    must be assigned to customer role ( registered )

but i fount that customer can add all 20 products with 0 price

but i need customer can have just one product discount and other no  

so what i must do
my version 4.10

Yes you are correct there is no plugin to do it now.
Essentially you need to search back through previous orders and compare the discounts to some predefined limits

If you have a look at this post it is the same concept just need to check the discounts instead of quantities
https://www.nopcommerce.com/boards/t/70715/limit-products-per-month-for-each-customer.aspx

Hi,
definitely you need a custom discount requirement plugin.
I can develop that for you. Send a PM for the price.