While looking for cool holiday lights to use on our next project inspired by this lit up canvas, we found these cool balloon lights. Much cheaper than the LED balloons AT wrote about last year, these balloons cost about three bucks each.
Each balloon comes with a self-sealing valve with an LED light attached to it within the balloon. The light is powered by three watch batteries, which can keep going for about 10 hours. If your balloon pops, the light can be reused on other balloons.
A few more photos after the jump of both inflated and deflated balloon lights...







My guess is that this method is cheaper, even though it may take a few extra minutes of work.
http://www.instructables.com/id/LED-Floaties-That-float-away/
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