Logitech sells a lot of different keyboards, and the K400 has been a popular option for years as a cheap wireless model with USB connectivity. The slightly-upgraded K400 Plus is an excellent keyboard for home media centers, Raspberry Pis, or any other use case where you need a keyboard and touchpad in a single compact device. Now you can get the K400 Plus for $19.99 at several retailers, a $5 reduction from the normal price.
The K400 Plus is a wireless keyboard that uses Logitech’s Unifying USB receiver (included in the box), so it’s compatible with anything that supports normal USB keyboards, and you still don’t have to deal with cords. The wireless range can also reach around 33 feet (~10 m), so it will definitely work from any couch — unless your TV is extremely far away. For power, you just need two AA batteries, which are included in the box.
This keyboard a great accessory for the Raspberry Pi and other micro-PCs, because it only has to take up one USB port instead of the two usually needed for a keyboard and mouse. The wide OS compatibility and compact design are great to have, too. Even for PCs with built-in Bluetooth for using normal wireless accessories, the K400 Plus is still one of the best budget couch keyboards you can get.