I'm going to buy a Huawei watch, so this seems like it would be good for me, because if I don't make another purchase to use the $15 I won't be out anything anyway.
https://bestbuy.cashstar.com/gift-card/buy/
Free $15 savings code with $150 in e-gift card purchase.
$15 SAVINGS CODE OFFER
Valid 11/5/17-11/18/17 online only.*
$15 savings code will be provided via e-mail on 12/1/17 for use toward a future purchase made from 12/1/17-12/14/17.*Maximum of 3 $150 e-gift card purchases during promotion time period per customer and savings codes will be sent via e-mail in $15 increments.*Valid e-mail address required to receive savings code.*Savings code may be redeemed online and in store.*The value of the savings code will not be refunded if merchandise is returned or an order is cancelled.