I would not spend my money that way, but it's not a con. The purchaser is not misled about what he is buying.

I would argue that, yes, dillondoyle is being misled about what he is buying. And he even admits the remorse of the situation:

"That's the magic. I always go in with one specific item in mind that I researched online but never leave with just one thing..."

There's intent that he's going after a single item that he researched and came to a decision. But extensive use of psychological tricks somehow weasels in extra things. Call it a mark of a salesman. Call it being taken for a mark. But it does have the distinct feel of something not wholesome.

I usually end up buying things in the supermarket I didn't explicitly intend to buy, and obviously the supermarket is set up in a way to encourage such impulse purchases, but I would not describe it as a scam. I am not reading any regret into that post.