Amazon is running a promo where they’ll give you $5 Amazon Credit just for “purchasing” select free Amazon Underground apps. Just head over and “purchase” either this app or this app. You don’t have to actually install the apps to get the credit. Just select “Cloud Only” from the “Deliver to” drop down menu. Once either app is purchased, you should get an email within minutes informing you of your free $5 credit. The credit can be used on “any eligible item sold and shipped by Amazon.com,” not just apps. The $5 credit must be used by February 26, 2016.