Answer:
Cognitive dissonance
Explanation:
Cognitive dissonance is the term which occurs or happen when the tension arises among the attitudes or beliefs of the person and the decision that contradicts with those pre- existing thinking modes.
In short, it means that it occurs when a person select among the two equally unappealing or equally attractive options.
So, in this case, Bill thinks that he had received the best deal for the car, but after purchasing, he noticed the disadvantages of the car as he learned regarding the new cars. Therefore, he is experiencing the cognitive dissonance.