You looked at something that looked like a collapsible potato gun with the label "Boob Tube" The employee said "Ah, the Boob Tube. Something made originally as a joke, and then got made in this weapon's aisle. It'll charge with magic over time, but it generally has two settings. A surprise setting and an immobility setting. The surprise setting makes it fire a round that's more smoke, and simply grows the victim's breasts a little. Designed more to surprise your adversaries and give you some time to run away or get cover. It uses relatively little magic and can be used several times before needing to recharge. The immobility setting has basically no smoke, and the victims in the attack's radius will have their breasts grow to car size effectively immobilizing them or entraping them if their surroundings are a little cramped. That can only be used once per recharge though. Both settings only last an hour."
Looking at the price tag you said "I'll take it." with it being collapsible it was able to fit in your pocket. Perhaps you'll need it some day, perhaps you'll have some fun with it sexually. One way or another you payed the price and now you have a Boob Tube in your pocket.