I couldn’t resist picking these up, the LEGO Star Wars Imperial Speeder Bike set #30005. I think I have 30 of them total, the result of finding a big batch of them, and a $10 off a $50 purchase coupon. Evidently, they are a pretty rare set, and a limited promotion of some sort. I think they appeared in stores in Fall of 2009 for the holiday season, and then reappeared in Fall 2010.
They seem to be the only way to get Stormtroopers in bulk without relying on buying bigger sets or the second-hand market. I bought them mainly for the minifigs, but was surprised at how nice the little speeder bike was. I will likely just add those pieces to my overall parts collection, you can never have too many brown and grey pieces.
I believe these worked out to about $3.25 each before tax. A pretty good deal, considering these minifigs typically trade for more than that on BrickLink. Then, you get the extra speeder bike pieces as a bonus.