Have you looked into the plaid[0] free(test) tier? They hook into a bunch of different banks and the free tier exposes balance and transaction history.
I really wish I could find a service that would do this for something other than Google Sheets (or like Tiller using a Google login even though they can write to Microsoft's OneDrive...for some reason). The last place I want to store a bunch of sensitive financial information is Mint. The second last is Google.
To that end, I looked into using Plaid's API to craft my own but it's a bit daunting, especially with a couple of my financial institutions continually failing and having to be reauthenticated, so I don't envy these developers their tasks.
It imports live bank transactions into a Google Sheet for you to use however you want.