That gets into a very hairy definition of "free." How much did Hacker News pay you for the time you spent commenting? Probably not market rate. Yet we'd still probably say that Hacker News is free.

I've never seen an interstitial on HN. Have you?

Yes, all the time. HN advertises jobs for y combinator companies and those ads are placed in between actual news stories.

So, it's free unless there's an interstitial ad? That seems like an awfully random place to draw the line.

It's not that that's not a real cost. Is that you don't include intangible things such as time and emotions when determining if something is free, by any expected usage of the word.

Hold on. My account balances are represented in a purely digital form. Almost all have no real physical record, at least not in sufficient detail or accessibility to be comparable to the digital form (in most cases it would probably be impossible to recover from a complete loss of the digital form). Most people here who use traditional banks and credit cards are probably in a similar situation. You are telling me that these numbers ($$$) that exist only as a pure digital artifact in some bank's database is a 'tangible thing'? But the time spent on the horrific and unsolicited intimate experience that you put me through with your ad is 'intangible'?

wut?

I should have said non-monetary.

The way Amazon is using "free" the definition means that you don't pay money for it. Full stop.

There are other ways of calculating what your "costs" are, such as including opportunity cost (what you're referring to as "time wasted." If you use that definition of "free," literally nothing is ever free, as you're always forgoing something else.