Just put a disclaimer that prices will increase in the future as more features are added. I think when I bought the app at $10 it wasn't worth it. Kind of like a toy that was cool for 10 minutes. Now with all the updates and running faster I think it's worth $15. Reconditioning doesn't do much for me so not worth $3 or even $1. I think even with more features, this could be a $20 app.
You just need to find features the $35k owners cares about. Let's call them non-Tesla rejectors. They have different needs than Tesla hardcore. They wouldn't care about data but more QoL issues. Once you get those in, this would be an awesome app worth much more than $20.
Btw, at $10, he was only taking in $7. Increasing the price means he is now taking in $10.5 before taxes. Just be glad he is sharing this hobby with us. Totally not worth his time to upkeep. Just UI/UX alone without any coding skills, we pay the artist $30k/ month. The income from this app is a drop in the bucket for this guy.