For the 2015 holiday promotion, get a bonus of 1500 Alaska miles when you spend $500 through Mileage Plan Shopping. This is on top of the miles you earn normally when shopping through the portal.
If you aren’t a big spender, you can still get 250 bonus miles when you spend $100.
It looks like you max out at 1,500 miles. If you spend $1,000, you don’t get 3,000 miles. The terms also claim that gift card purchases are ineligible for the promotion, but YMMV (your mileage may vary… no pun intended!).
If you don’t have an Alaska Airlines Mileage Plan account, I would suggest you sign up for one. Alaska miles are some of the most valuable and can be redeemed for great First Class tickets with Emirates, Cathay Pacific, and other partners. I’m taking a round the world trip in First with my Alaska miles.
It doesn’t seem like you need to opt in; just sign in and shop as normal.
The 1500 Alaska miles when you spend $500 through Mileage Plan Shopping promo runs through November 20th.
Full terms (thanks to Oren’s Money Saver for sending these to me, for some reason the page won’t load for me):
*During the “Holiday” bonus campaign, which runs from 11/10/15 through 11/20/15 at 11:59:59 pm ET (the “Bonus Period”), Member will receive a one-time bonus of up to 1,500 bonus award miles on qualifying purchases, in addition to the standard miles earned from shopping online through Mileage Plan Shopping. Bonus miles will be issued based on Member’s cumulative qualifying purchases made during the Bonus Period: 250 bonus miles for qualifying purchases of at least $100; or 1,500 bonus miles for qualifying purchases of $500 or more. Returns, cancellations, shipping and handling, taxes, gift card or other cash equivalent purchases, and certain products are not included in the bonus award miles eligibility calculation; please see the Mileage Plan Shopping site for details on product eligibility and/or any coupon code details or other usage restrictions. Please allow 8-10 weeks for bonus award miles to post to your Mileage Plan Shopping account. The maximum number of bonus award miles that will be awarded to an eligible Mileage Plan Shopping account through the bonus period is 1,500 bonus award miles. This offer cannot be combined with other offers or promotions. Please check the Mileage Plan Shopping site daily for updates to increased earning opportunities. Void where prohibited by law. Increased miles earning opportunities are for a limited time only and at the discretion of each individual merchant. Miles earned through shopping generally post within 5-7 business days.