Low power LED (3mm)
100 or more: $0.15
Low power LED, 3mm, 2ma, diffused tinted, forward voltage: ~1.8-1.85V.
Used in various Moteino projects, can be used with a 1K-1.5Kohm resistor from a 5V or 3.3V Arduino/Moteino pin.
This will save power significantly over the regular LED that uses 20mA.
Use 1K with Green, 1.5K with Red/Yellow.