Just a quick post today, received this in the mail from China today. A USB voltage and current tester for a whole $2
Nice simple setup plug one end into a USB port and connect the device you want to the other end and the display changes back and forth from current to voltage every few seconds.
Measures 3.5-7V and 0-3A.
Lets connect it up:

4.91v

0.08amp.

Nice simple device that does what it says on the box and quite useful for diagnosing USB devices, well worth the $2 to have around for the odd time you even just want to know how much current you’re getting out of a charger.