I accidentally stumbled upon a voucher giveaway for second shot exams on the MCP website. You can either get 15% off for a certification pack or a free second shot for a single exam.
Simply go to this page, select the second shot or the certification pack from the table, fill out the form and the voucher code will be sent to your email address. It’s valid till the 31st of May 2013.
Don’t forget to enter the voucher number when you schedule the exam.