Dropbox, being the de facto leader in paid cloud storage, rarely offers any discounts on its 1TB "Pro" service. But lately that seems to be changing, if only through Dropbox's retail partners: Dell offered a sizable discount on a year's subscription plus a gift card last month, and now Amazon is doing something similar. Head to this link and you can purchase a year of premium Dropbox service for $99, with a free $50 gift card for Amazon, effectively bringing down the price to just $49.
There are a few caveats. One, the offer is only available in the US, which is a bit of a bummer considering Amazon's international status. It's also not available for existing Dropbox Pro or Business subscribers, not even as a code you can keep to re-up later - Amazon's ToS for the sale says that service must begin on the day of purchase. (You might be able to wait out your current package and buy this discounted version when your storage shifts back to Basic, though.) Also, purchasing through Amazon will add Dropbox Pro as a recurring subscription in Amazon's Digital Orders system. It's auto-charged upon renewal, but can be cancelled at any time.
The Amazon gift card is a little less of an actual rebate than Dell's deal, but since Amazon offers so much more on its digital storefront, the credit is practically spendable as cash, especially if you're hunting for holiday gifts. The extra storage is accessible from all Dropbox tools and apps, including the web, Android phones and tablets, and desktop operating systems.