If you have a subscription, you might not need to pay extra. Many services allow you to "download" within their app:
: Provides digital copies for download to Android and other compatible devices. The Secret Life Of Pets -English- Download
Check if English SDH (Subtitles for the Deaf and Hard of Hearing) are included if needed. A Note on Safe Downloading If you have a subscription, you might not need to pay extra
Here are the sources to download or permanently purchase the English version: If you have a subscription
(Kevin Hart), a "psychotic" but adorable rabbit who leads the Flushed Pets