Sometimes you can find some cheap sunglasses in summer. Have you heard about that lower the price can make a bigger profit? So sometimes the stores just use this way to broadcast their products as well as make bigger profit. But as to any physical shops, they won't sell products at lower price in best season. They will sell products at lower price in off season. So if you want to buy a pair of sunglasses online, you'd better place an order when there is some activity or celebrations hold by online stores. If you want to purchase them in any physical shops, I suggest you to buy them in off season. Though you can't wear them at that time, but you can wear them in the next summer and this can save your money.