A simple way to implement Squareup payments?

Hi folks.

Hopefully this is the correct place for this. In the past, Square allowed simple embedding of Square Marketplace items on a website. For no clear reason, they no longer allow embedding. I only need to sell a couple of items, and only on occasion. I also don’t want to turn my entire site into a “store”. Just a way to include an item or two on a given post or page.

Any suggestions would be appreciated.