There's no chance I accidentally buy $10,000 worth of staplers when I walk into Office Depot though, while the opposite is extremely easy in AWS. Plus, when I checkout I'll get an itemized total of what I owe before I pay, I won't be charged an unclear amount at a future date.
That line of reasoning is wrong. I'm sure there are consultancies that specialize in office stationery procurement; doesn't mean anything for your small use case of buying a few pens for your home office.