I needed a new keyboard and mouse for my Raspberry Pi. My mouse was unresponsive, and my keyboard was repeating letters. (startx became sttttttartttxxxxxxxxx) I found the Logitech mk270 on Amazon, and I am thrilled with it. Here it is:
That tiny little thing is the wireless receiver.
The keys are nice, but the stand on the keyboard is a bit weak. The mouse is good. Both parts are very light.