Welcome to the Fitbit Community @Katiemcwilli. I am sorry for the delayed response.
I am glad to assist you with your concern about how you can pay for the clock face. Some apps and clock faces require a paid subscription service (such as Pandora and Deezer) or a one-time activation fee (to a developer). If a developer requires an activation fee, you may see a message in the app or clock face description. For these apps and clock faces, the developer will process and provide instructions for payment. Many developers use the third party service KiezelPay to accept payment for their app or clock face. For more information, see KiezelPay’s FAQ. For more information, please see this help article: How do I install and manage apps on my Fitbit watch?
You can find the steps to change the clock face in this help article: How do I change the clock face on my Fitbit device?
If you have any questions, feel free to let me know.
Want to discuss ways to increase your activity? Visit Get Moving in the Lifestyle Discussion Forum.
