The consumer

Whether the consumer knows it or not, they (and their purchases) are the drivers of affiliate marketing. Affiliates share these products with them on social media, blogs, and websites.

When consumers buy the product, the seller and the affiliate share the profits. Sometimes the affiliate will choose to be upfront with the consumer by disclosing that they are receiving commission for the sales they make. Other times the consumer may be completely oblivious to the affiliate marketing infrastructure behind their purchase.
Either way, they will rarely pay more for the product purchased through affiliate marketing; the affiliate’s share of the profit is included in the retail price. The consumer will complete the purchase process and receive the product as normal, unaffected by the affiliate marketing system in which they are a significant part.