"Of course you can change back," the man said. You sigh as if a weight had fallen from your shoulders. "I'll cast a permanent spell on your old pants to return you to your original form when you put them on."
"That sounds great, actually," you say. "Wait, 'permanent' spell? As in...?"
"You can go back and forth between your current state and your original one, whenever you like and as often as you like, provided you choose to purchase the jeans you're wearing. The entire purpose of my wares is to offer people different options for unique experiences, not to trap them in another lifestyle." The man gestures around the store. "As a first-time customer, I will give you those pants at half price, or I will take the full price off an extra item of your choosing."
Free stuff sounds good to you right now. Knowing you aren't stuck the way you are opens your mind to considering your present state. You can't deny your curiosity at exploring what life is like in this new body, though you want to return to your old form soon.
You look down at your stocking feet. If you wore these jeans out of the store, you wouldn't be able to use your old shoes. They're too big for you now. And you could buy a new pair of shoes for free if you take the man up on his offer. Or do you want to forget these pants and try on something else?