Young or old, oily or dry, a primer is not just something to make your makeup last longer, its something that provides a great base for your products to fuse to, it hides a multitude of sins, can mattify oil or add glow and will help your products look better and last longer. My primer obsession right now is SMASHBOX photo finish primer water - It retails for £20 so its pricey, but just a spritz or two before you apply your makeup makes all the difference and it because you need so little to achieve amazing results it will last ages. It has a lovely clean refreshing scent and I love it. For coverage of Acne scars you may want to try out GOSH velvet touch line perfector - it doesnt fill deep scarring but does help it appear less obvious under makeup. And for helping those pores appear less visible you really can't beat L'Oreal magic blur - it has a strong smell, but it quickly fades, and the results are great. It really does give a nice smooth look to the skin.