You can install our eCommerce app on your Google Sites. Customers will be able to make a purchase with their Visa or Mastercards provided that you toggle Connect to Stripe Payments on and they have a Stripe account:
However, please be advised that this is a paid feature available only on our Starter plan. So, to be able to use it, you will have to buy an upgrade for your eCommerce app.
Please visit this link to see the features and pricing for our eCommerce app: https://www.powr.io/pricing
Make sure to choose Ecommerce to see the corresponding price table.