Got an old phone that you could sell for £10 online? DONT! Turn it into a mini TV / Games console!
Simply print this Retro TV cover, stick your old smart phone into the back using hot glue or double sided tape, download a free TV app and games console emulator and off you go! Your old phone is still a computer (think of it as a Raspberry Pi with a screen), it should still receive WiFi, and be able to carry out multiple tasks such as online browsing.
My old phone is a Sony Xperia, the two holes for the headphone jack and micro USB align on this model but you may need to adjust their positioning as necessary. Same with the screen size, measure your screen (and outer dimensions of your phone) and adjust as necessary. You may also wish to experiment with a raft (or not) and infill requirements.