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.
To act like that is not a real cost is...baffling.
wut?
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.