E-commerce package with no front-end

Is there any good packages to add e-commerce or tutorials that dont have a front end? I am building a website where a store will be a small part of the site so I dont want a full out-of-the-box solution since I have my whole frontend and admin already. What would be nice is a proven package where I can just use migrations and functions where I need and do all the front-end and admin on my own.