Palmers Cocoa Butter body lotion, it's got a gorgeous thick heady scent to it, and is only around £4 for a bottle which will last about two months.
I have used it for the past few months on stretchmarks I have on my belly, it can't make the skin tighter, but better moisturised skin is plumper and therefore shows stretchmarks less, and heals much more quickly.
Exercise will help tighten skin through time. Muscle is sort of meatily glued to your skin, so areas which are looser can be tightened up by toning. It's a LONG process though, but worth it if you're willing to stick to it! It won't reduce the actual scarring, but again will improve the area making it less noticable.
Keep it moisturised and VERY VERY VERY VERY gently exfoliate them, like with table salk mixed into shower gel so it's a quite watery paste.
Rough exfoliating will only cause more skin damage.
If they are new and still red, I would suggest trying Bio Oil or Johnsons's baby oil. When they are red is the best time to start treating them really, if they are already silver/white, the damage has already healed.
Sadly you can't get rid of them entirely without surgery, but you can do lots to make them fade and appear less angry.
Hope that's of help!