I want to drive around 80 LEDs from an Arduino with 10 8-bit shift registers. (Some will be RGB LEDs; I count those as 3.) I know of the TPIC6B595 high power shift register but it's expensive: 1.75 USD from DigiKey and Mouser. I would prefer to do this cheaper.
I can get 74HC595 low power shift registers for 50 cents and ULN2803A Darlington arrays for 65 cents from Futurlec. That is a total of 1.15, so I'd save $6 on the whole setup.
But the ULN2803A is way overpowered for LED's - each pin can sink 500 mA! Is there anything similar to the ULN2803A, but lower power and even cheaper?