Great point, definitely need to add the pricing to our website!
And no, we're not an open source app. In terms of pricing, we have a Free tier and a $10/month "Journal Plus" tier.
Currently the differences between Free vs. Journal Plus are:
1. number of app integrations (2 vs. unlimited)
2. amount of data synchronized from those apps (last 14 days vs. years)
3. file size upload limit (10MB vs. unlimited)
One commitment I can make is that we'll never monetize off of your data or by dumping algorithmic ads on you. So, to do that, we're creating a subscription scheme that allows us to provide some powerful but expensive features, but also provide a very useful free tier.