In general, there are several types of e-commerce sites. However, the most common ones are business-to-business (B2B), business-to-consumer (B2C), and consumer-to-consumer (C2C). The B2B type markets its products and services to fellow businesses, which can be from a different industry. B2C provides goods and services directly to consumers.
C2C is when the sellers are consumers that offer products to consumers through an intermediary. For example, eBay, Amazon, and Facebook Marketplace.