As a paid user I should be able to add prices to the series that are already in my collection

[php-coder]

After transition from a simple user to a paid one, there should be a way to add prices to the existing series in a collection. At this moment, the only way is to remove a series from a collection and and it again but it's confusing users and might be non-obvious and tedious.

Reported by our user.

[php-coder]

We can place it to the collection estimation page, in the block where price should be.