38, but each order usually contains at least 10 items. I do about 80% of my shopping on there.
As a service it's just unbeatable. Order what I need and select to have everything delivered at the same time and on the day of my choice. Parcel tracking, free returns, prime video, music etc are all nice features too.
People are also often given a lot of amazon gift vouchers as a bonus by their employers and the resale market for them is pretty strong. The resale value is typically 92.5% so I just buy these up and credit them to my account. I end up paying less shopping on amazon than I would elsewhere.