What is The Decoy Effect?
Companies add a deliberately poor-value middle option priced close to the premium tier. Compared against the decoy, the premium tier looks like a bargain.
Where it comes from
Huber, Payne & Puto (1982)
How it hooks you
Exploits asymmetric dominance: an obviously inferior option shifts your sense of what counts as a reasonable price.
How to resist it
Decide which tier you actually need before looking at the comparison table.