Amazon is offering the Logitech K760 Wireless Bluetooth Solar Keyboard for Mac/iPhone/iPad for $29.99 with free shipping for Prime members. All other buyers will need to spend another $5 to sidestep shipping costs.
This keyboard is able to charge itself from lamplight or sunlight, indoors or outdoors. It can even operate for 3 months in a dark room off a single full charge. The Easy-Switching Bluetooth connection supports up to 3 unique devices. Compatible with most Bluetooth devices including the iPhone, iPad, and Mac. Rated 4.5 stars. 9to5mac reviewed an earlier version of this keyboard and loved it.