You can create a collection with the fields you need (product name, image, price, owner name …), allow members to submit and read from this collection (in the collection settings) ,
Then create a form (with user input) and connect it to your collection (so when a user fills out the form, the information will be uploaded to your collaction).
Next, you’ll connect a repeater to the same collection so you can show what users are posting to the collection.
Read more here : CMS: Changing Your Collection Permissions | Help Center | Wix.com