Ability to add seats

[tnerbovik]

It would be great to be able to add seats on a subscription. Often a requirement when business owners can pay for employee access etc.

[nathansnelgrove]

This would be useful in other cases too, even if it wasn't called seats. Allowing folks to purchase quantity units of each subscription would go a long way to helping nonprofits who need recurring donation products. You could set the price of the subscription to $1, and the quantity field ends up dictating total price.

(Obviously, this isn't the ideal use case for this feature, but it's proof that's useful in multiple ways.)