The Amazon Appstore is installed to your phone memory, not the SD card, so that 7.4GB means nothing when it comes to installing apps(unless you move them to SD after installing). I think the Evo has like 300mb of storage user available. Thats one of the main downsides to HTC phones vs Motorola. HTC is very skimpy on memory storage with Sprint phones for some reason. I dont know if its a HTC or Sprint thing.