look on your receipt or online. usually the return policy is on there and generally speaking you can go back and get the lower price in the same amount of days that you are allowed to return the item,

Well not really…just sneak it.
Return it, and then buy it again in like…20 min.

No. This would not work because even if you went to return it, if the store accepts returns, for say a size difference, you would get the money you payed refunded and the same price charged right back to you. If it was on sale when you bought it, you would be able to get the sale price refunded and then charged again but you haven’t so the answer is NO.
Sorry

Just buy another one and return this one. Wouldn’t it have been easier if you just called them and asked them about their policy?