So far I have purchased THIS 780nm 5mw IR Laser Diode from ebay. Total cost: $12 shipped.
I have taken apart an old junk laser that came on an entry level AEG and removed the laser diode from it in preparation for when the IR laser arrives. The laser holds 3 small watch batterys that are 1.5v each making it a 4.5v cell, which should run the IR laser just right. Cost: Free, most of us have one laying around somewhere


Once the laser arrives I should have more to post up, but until then here is a video I found on Youtube of a 5mw IR laser viewed with night vision.