Earlier this week I bought a package of 3 LED "puck lights" at Costco
for $15 US with batteries.  These ones are a little bigger, about
3.5" in diameter and grey in color.  They use 3 AAA batteries each.

The Costco ones come with stick on Velcro and screw mounts, have two
brightness settings, and are pivotable so you can aim them better
than the "DotIt" style.  I agree with Nathaniel, a few of these units
and you have plenty of light for camping--and with LED's, the
batteries last a long time.