Is it possible to design a product page in html and then bring it into Pinegrow and then add things like add to cart button, price etc… using Pinegrows functions?
Pinegrow is like a massive toolbox that lets you do anything you want with HTML, CSS and Javascript, but the only “pre-made” elements are those found in the frameworks it supports (like Bootstrap, Foundation, etc.)
You can certainly add buttons, prices, and front-end functionality with Pinegrow, but Pinegrow has no built-in shopping cart system, or e-commerce tools, or back-end/database integration.
I presume you could get the Wordpress version of Pinegrow, build a Wordpress store front-end, and using the WooCommerce plug-in make it into a functioning e-commerce website, but that’s outside my area of expertise. I do not use Wordpress at all.