There's a bitter divide in the world of Android hardware: those who love expandable storage and those who don't. (There are a few who are indifferent and level-headed, but they never seem to speak up in the comments section.) If you fall into the former category, head over to Amazon's Gold Box one-day deal page. They're selling Transcend brand MicroSD cards for dirt cheap.
You can pick up a 32GB MicroSD card for $13.99, more than $20 off of Amazon's regular price. The 64GB version, normally a full fifty bucks, is just $28.99 today. Both cards are rated Class 10 for speedy file transfers and photos, and come with free adapter sleeves for easy transfers to cameras or laptops. These are the only MicroSD cards available in today's sale, but those looking for standard USB drives, external hard drives, or full-sized SD cards can probably find some worthwhile deals as well.
As always, Amazon's Gold Box promotions are for one day only, and Amazon Prime subscribers get free two-day shipping. These cheap cards are usually a hot item, so you might want to grab one before they go out of stock.