The journalist may suffer from misconceptions, but the version of the experiment to which these results apply was conducted so that the transaction costs were equal in either case (source: https://people.duke.edu/~dandan/webfiles/PapersPI/Zero%20as%..., see Experiment 3).

> Well obviously, I'm getting a free thing as a no-brainer, and then I also decide whether I want the paid thing or not.

Not permitted. If you take the "free" chocolate they will not sell you the fancy one at any price. It is not obvious how people behave under that circumstance.