Non-invasive Low Current Measurement
Other than hall effect sensor, if you have a current probe..   


set it to the best possible settings.. (just an example:  2A per 1V instead of 2 A per 100mV)..  
Roll the wire 10 times around the clamp in the same direction. Now, on the oscilloscope you will measure \$10 X\$ the actual current through the wire.   




For the update:. 

If you are planning for multiple, hall sensor is cheaper and practical.