The Grid can absolutely be used for ecommerce right out of the box. However, you'll need to have a shop and payment solution in place. This can be anything from Shopify, to Etsy, to Paypal. The choice is yours.
Check out this example http://thegrid.ai/basict/ that uses both Call to Actions out to the product page, and also iFrame embedding to have it on the main page. They used Typeform to set up a shop. It works well because it can integrate with Stripe and you can also sell multiple products as you can see. However, you can do something similar with almost any shop solution on the web.
This site set up an external Call to Action for the button at the top. They also embedding iFrame to have it on the main page feed. You can do this by getting the embed code from your shop service and using the Embed HTML feature in the post editor. Here's how you can do the same:
After you create your order form or product page head to the Share tab. You can copy the share url in the Share your typeform section and create a Call to Action using the link. You can also grab the code from Embed in a web page section and past it into the editor using the Embed HTML feature.