How to change price of an In App Purchase Subscription in iTunes Connect
Select the product and under Subscription Prices tap on View all Subscription Pricing.
In the Subscription Prices tab of the new screen select Starting Price below the Current Prices title:
And then Edit Price Change in the new screen that appears:
Finally select Recalculate prices for all territories and follow the instructions:
Update for people using the newer portal (aug 2020)
It seems like you can now only update the price at the earliest, starting the next day.
- Click on "Manage" under In-App Purchases in the left sidebar
- Click on the subscription from your group you want to change the price for.
- Then click on the plus on the right "Subscription Prices" and select "Plan Subscription Price Change"
- Select all your regions and click next
- Select the start data (earliest tomorrow) and the new price
- Double check the new prices for all regions and click next
- Then agree to the price change and click done
- Lastly, very important, don't forget to click "Save" in the top right. Since you won't get any pop-up about disregarding the changes you have made. I for one, forgot this and a few days later realised that some price changes did not happen.