I believe what @Benjamin_D is talking about is that by using or integrating with WordPress, you should be able to create a shop-like part of your forum, where the shop is on WordPress and the forum is connected to it.
You can also use theme-component to make the topics on your forum appear like they would in an online store. Some theme components that fit this or may be helpful to you are:
- Topic List Thumbnails Theme Component - theme - Discourse Meta to allow product images show on the topic list
- Topic List Excerpts Theme Component - theme - Discourse Meta to allow product descriptions show on the topic list
- Linkify words in post - theme - Discourse Meta to automatically add links whenever a product name is used
And so much more. A good way to go about this would be to sketch how you want the forum to look and search for specific integrations to help. Asides this, I do not know of an out of the box solution that creates a shop of your Discourse forum.