You can find our premium subscriptions at sheetgo.com/pricing. Subscriptions are limited to the number of connections you create and connection-related features.
For example, if you choose a subscription with 100 connections, then in theory you can create 1 connection on 100 different spreadsheets to reach that limit. However, you could also create 50 connections on a single spreadsheet and spread the other ones on other spreadsheets.
They way you allocate your connections among your spreadsheets is up to you.
We hope that helps! If not, please let us know at firstname.lastname@example.org.