We can already use microformats for some of the data points:

💁🏻‍♀️ Mary sells a 📠 scanner to 💁‍♂️ Marc for 💶 EUR 80

👉 data points:

Parties: 👨‍👩‍👧 h-card
💁🏻‍♀️ Mary
💁‍♂️ Marc
Transaction type:
Sale 👉 Transfer of ownership and transfer of money
Object: 📦 h-product
📠 Scanner
Price: 📦 h-product (partially)
💶 Currency: EUR
💸 Amount: 80