From the Windows Phone Developer Blog:
“Windows Phone 8 is out, the tools are available, and devices are about to be released—it’s time to get coding. As an added incentive, for the next 8 days individual developers can register for a Dev Center account for just $8 (a 92 percent savings). Please note because this is a very limited time offer. You’ll be charged $99 USD or equivalent in your local currency, and we’ll refund the difference in the next 30 to 45 days. Watch for more details on Dev Center soon.”
So, if you’re interested in getting your apps on the Windows Phone platform, this is a great way to get started.
For more information, check out this blog post.