This offer is only for those with a Kindle with Special Offers:
Get $15 off a $50 swimwear purchase at Amazon.com
Click on offer, then click on the link on the offer page to receive an email with the promo code. Sign-up for this offer expires on February 19.
You'll get an email (right away), a link to the Special Offer page and a promotion code to enter at checkout. Once you have the promotional code, you have until March 19, 2012 to complete your purchase. Like previous offers, this one requires you to use the full checkout process in order to enter your promotional code. Also, like all Amazon sales that use promotional codes, if you have a gift card balance, you must use it for the payment (if there is not a sufficient balance, then you can pick which credit card or other payment to use).
Limit one offer per customer and per device.
Shop early, of course, as their selection often dwindles as the offer goes on, but this early in the year, they shouldn't sell out of too much. This is a bonus offer, that isn't on the "normal" schedule (every 4th day), so you may not have though to check your Kindle today to find it.