No. You choose a plan and approve its monthly price on Shopify's screen, and that price is the most you pay. Billing goes through Shopify and appears on your Shopify invoice.
Trial — the 7-day free trial is once per store. After it ends, Shopify charges the monthly price you approved. If you switch plans or reinstall, only the unused trial days carry over. If no days are left, the plan card says "No trial — billing starts immediately at $X". Views during the trial count towards Growth's 20,000.
Growth's view limit — at 80% of your 20,000 views, you'll see a warning on Plans and Home. At 100%, pop-ups stop showing on your store ("Monthly views used up") until the counter resets or you move to Unlimited. The counter resets every 30 days from the day your plan started (including the trial), not on the calendar month, and the reset date is shown on the page. This view cycle is separate from Shopify's billing date, so the two dates can differ by a few days.
No extra charges — there are no overage fees and the app never upgrades you automatically.
If you decline the charge on Shopify's screen, nothing changes: a store with a plan stays on it, and a new store stays on the Plans page.
Development stores — free while the store is in development. When it becomes a live store, you'll be asked to choose a plan.
If a charge doesn't match what you expected, chat with us and we'll go through it with you.