£7.49 for Metal Gear Solid: Ground Zeroes. That's the best price you'll see for the prequel to Metal Gear Solid V: The Phantom Pain as you're likely to see in the next six months. I've been looking for a decent deal for this one for months and I've not seen it dip below £15 at retail. You're looking at around £17 if you want a disc version today. I'm snapping up this one as you know the disc will have a fat install anyway and chances are I won't want to sell it when I'm done. Note: You need a PS+subscription to get this discount price, but if you have a PS4, you probably already do.
Ground Zeroes has some excellent replay value beyond the initial short run through the story as there's loads to discover around the base. Don't forget, a recent patch has added the previous platform exclusive Raiden and MGS1-style missions to each version. Check out Jon's review if you're still on the fence.