Why some users buy a product with higher price?

I recently talked to a person who is a supplier for an E-commerce website. In this website suppliers can provide their products at the price they choose. So it is probable that a specific product is available at different prices. He said that sometimes although the product is available at a cheaper price, there are some users that buy the product with higher price with same warranty and specifications. Sometimes they pay 50% higher price.

How do they think?