buyer's remorse

An acute sense of regret following a purchase, especially an expensive or extravagant one, due to conflicting feelings of guilt or uncertainty about the decision. I was so dazzled by the new car that I signed the contract right then and there, but I started having terrible buyer's remorse the next day after I thought about how much money I'd spent. She tried to convince herself that the new computer was something she really needed, but she couldn't shake that terrible feeling of buyer's remorse. I always think shopping will make me feel better, but I usually end up with buyer's remorse, wondering why I bought all this stuff I don't need.