E-commerce companies make money through various avenues:

1. **Product Sales**: They sell goods directly to consumers, often at a markup from their wholesale purchase price.

2. **Service Fees**: Some charge fees to sellers for using their platform to list and sell products.

3. **Subscription Models**: Offering premium memberships or subscriptions for additional perks, discounts, or faster shipping.

4. **Advertising**: Generating revenue through advertisements placed on their platforms, similar to how websites earn through ads.

5. **Data Monetization**: Selling anonymized user data or insights to advertisers or third parties for targeted marketing.

6. **Affiliate Marketing**: Earning a commission by promoting other companies' products or services through affiliate links on their platform.

7. **Cross-selling and Upselling**: Recommending related or upgraded products to customers, increasing the average transaction value.

These revenue streams allow e-commerce companies to monetize their platforms and services beyond just selling products directly.