Whoo-hoo! Now, I personally don’t believe that developing for the Windows Store was ever that expensive (an individual account used to be $49/year, and it is $99/year for iOS developer registration), but it has gotten even better! Starting today, you can develop for both the Windows Store and the Windows Phone Store for the single low price of $19/year for an individual account. It is still $99/year for a company account. I explain the differences between an individual and company account in this post, and it is also documented on MSDN here.