Volunteer: WordPress doesn’t comes with e-commerce built-in, but that functionality can be added by several plugins: https://wordpress.org/plugins/tags/e-commerce
I haven’t used any myself, but if you want a starting point, I’ve heard some good things about WooCommerce, WP eCommerce, and eShop. All of the plugins at the link above are free to use, so you can certainly try them all out until you find one that matches exactly what you need.
User: Help! My website has been hacked!
Volunteer: You probably used terrible passwords or left your computer open somewhere. Get a backup from your host or start over, and try harder to protect your work next time.