It's been a few years since I built a Shopify store but iirc they give you an HTML/JS/iFrame "snippet" of your products you can copy paste anywhere you like.
Indeed. Nice work, but it feels like you're circumventing the exact restriction of the Lite plan. I imagine they'd shut you down if you got too much business.
> Whether you’re on WordPress, Squarespace, Tumblr, or anywhere else, with just a few clicks you can turn your website into an online store.
1 - https://www.shopify.co.nz/lite