Power Supply 0-12v/20mA-3A for a reasonable cost

I'm looking for a variable power supply roughly 0-12v but more importantly one that can fine tune the current. I don't want it to cost a fortune around $100 would be preferred. I found a Mastech HY3003D (~$100)but it has a 100mA minimum according to the reseller. I found a BK Precision but it was $275. I need something that can go in 1mA increments through the 15-50mA range. Does this exist? I would consider 3 or 5mA increments if I must.

This is an unusual requirement. You are asking for a 3A supply that can adjust its current limit to a precision of 0.03% (1mA/3000mA). Most of the time we use the current limit just to protect the circuit. Are you using it as a Current Source?

This won't be cheap.