I need to manage price changing subscription with Stripe

Hello all!

I need to create an app that charges the user based on the items that they choose for their subscription. Depending on the items they choose, the subscription price will change, and once the user selects the item he wants, he will pay via Stripe.

I cannot see how Stripe can do that. It seems that it can only manage fixed-price subscriptions.

Any ideas?

End one subscription and start another?

I think it will be clear with an example.

If I select item A, item B and item C out of a catalogue of products that I offer, the user will have to pay a subscription that is price A + price B + price C. How do I tell Stripe to create a subscription based on what the user has chosen?