We bill $8 upon signup to cover that month's fee. After 30 days, we bill you for your next monthly fee ($8) plus your usage (in segments) x $.04 per segment. Go to https://sheetgurus.com/account/billing to see the amount due upon the next invoice.
For some folks who exceed certain usage tiers, they'll be billed once they exceed those usage tiers and not after 30 days.