You can purchase a battery anywhere LiPo batteries are sold. They are not proprietary or uncommon. You just need to make sure the battery is compatible with your specific kit.
For Home Original 
Here is a compatible battery on Amazon:
https://www.amazon.com/Battery-Connector-Airplane-Quadcopter-Helicopter/dp/B09T36BBXT
Or you can use the following specs to purchase one locally or anywhere else LiPo batteries are sold:
11.1v LiPo battery
3 cell (3S)
1550 mAh
25C or 30C (discharge rate) this number should be below 60C
- The mAh - number indicates the capacity - so the larger the number the longer it will last. Click here for a larger capacity battery on Amazon: https://amzn.to/3ILiHn6
- The number followed by a "c" indicates the discharge rate - ideally this should be below 60
The connectors are: XT60 connector (plugs into main drive) & JST-XHR-4P connector (plugs into battery charger)
For Home Plus 
Here’s two compatible options,
This would be a little less capacity:
https://www.amazon.com/Zeee-Battery-3300mAh-Airplane-Helicopter/dp/B08NDV319
Whereas this would be a little more capacity:
https://www.amazon.com/OVONIC-Battery-6000mAh-14-8V-Connector/dp/B0CLLSFFZZ
We like RCBattery.com for their quality and reliability: https://rcbattery.com/liperior-4000mah-4s-30c-14-8v-lipo-battery-with-xt60-plug.html
Or you can use the following specs to purchase a 14.8v battery anywhere LiPo batteries are sold:
14.8 volt, 4 cell, LiPo battery
5000 mAh
25c (up to 60c)
- The mAh - number indicates the capacity - so the larger the number the longer it will last.
- The number followed by a "c" indicates the discharge rate - ideally this should be below 60.
The battery needs to have these two connectors: The JST-XHR-5P connects to the charger. The XT60 (colors may vary) connects the battery to the drive.