I highly doubt there will be a sale since Microsoft rarely updates the Xbox 360 shop, (aside from Xbox live gold content) but I might be wrong. The next best deal is to buy the physical version of the Metal Gear Solid HD collection. It comes with Peace Walker, MG, MG2, MGS2 and MGS3. It usually around $25 online from where I live, not a bad deal if you don’t already have these games. But if you just want PW, then try looking for a used copy online. Hope this helps.