You can dynamically specify the price ID. One way to do it between live and dev modes would be to save the live price id in your live bubble DB and the test mode price id in your dev mode bubble DB.
Create a thing of type Subscription. Add a field called Stripe Price ID. Then when you are subscribing the user to a plan click on dynamically specify plan. In Stripe Plan Name simply Do a search for Subscription’s Stripe Price ID.
Just make sure that you save your live price ID in the live bubble DB and you’re golden.