$1 each:
USB to MicroUSB (like this) - I have 10+ of these of various lengths and colors. Get one free if you buy something else from this list
USB to USB3.0 (like this) - have a few
High Speed USB 3.0 Cable - A-Male to B-Male
3.5 mm Male to Male Stereo Audio Cable
3.5mm to 2-Male RCA Adapter Audio Stereo Cable

$3 each:
Ethernet cables - have a few
HDMI to HDMI
HDMI to mini DisplayPort adapter
HDMI to mini DisplayPort cable
VGA to VGA cable