The latest Humble Indie Bundle, which offers farcical bang-for-buck, has been for many a great way to get a load of great games for a reasonable price. Sadly, for others, it's been a way to try and scam a very lucrative competition.
Right now, Steam is running a frequent competition whereby it "raffles" off free games to owners of a Steam account. To increase their chances of winning this competition, then, some people are paying one single cent for the Humble Indie Bundle then using the bundle's associated Steam keys to improve their number of entries, and thus their odds of getting free games.
As a result of this, the Bundle team has had to remove Steam keys from all bundles being sold from here on in, meaning those generous, legitimate customers who wanted said keys with their purchase are now being stiffed.
UPDATE - The bundle team has actually instituted a change where purchases must meet a minimum threshold of $1 before receiving Steam keys. The information originally posted was incorrect. Apologies for the confusion.
$1 Min. Price For Getting Steam Keys [Humble Indie Bundle]