First Print Free With Option To Pay For Additional Prints

I have teams where I sell the team a package that includes 1-Free Individual poster and 1- Free Team poster for each player.

I want the parents to select their Free poster, then have the option to pay for additional posters.

They have multiple poses to choose from and some parents want additional posters of the other pose(s)

I have tried quantity discounts and if there is only one pose selected it's free, if I add another pose, of the same type (Ind or team) it charges the extra pose price for both posters, so no free poster. If I select 2-Ind and 1-Team the Ind are $15 each and the Team is $0 because I have them in different Product Groups.  I have the Item Price set to 0, then 2-0 set to $15 each under the Quantity Discount.

Would need this for Individual Posters and Team Posters

Is there another way to do this?

Sounds like the best thing to do is give them a Print Credit free products, then they can purchase additional products from the price list. I can't think of another way to accomplish that.