I'd look for some surplus 12V or lower DC solenoids.
A quick Google search (surplus solenoids) turned up these 6V 370 mA units for $1.59 each:
http://www.electronicsurplus.com/Item/7678/GUARDIAN%20-%20Solenoid_%20DC_%20Coil_%206VDC%200_37A%2016%20Ohms_%20-%20A420-066410-00/
Remember that you'll need a transistor to drive each solenoid. You should also put some fairly large (100 to 1000 uF) capacitors across the power lines to provide for quick current spikes.