Some of the Previous projects I have worked on, take a look!
This was a full e-commerse site with a fully functional user interface that included a log-in feature that used firebase for authentication with stored usernames and passwords, as well as holding other user data. The user may select items to buy using a basket feature, built with React Context, that will hold data reguardless of what page the user is on, the user may then may purchase the items at checkout with a Stripe component that accepts a credit card and connects to Stripe for processing after authenticating the request.