I use coconut oil. Sadly, it doesn't really matter what you use. It's largely genetic, and the only thing you can do is make sure your skin is hydrated to give it a fighting chance. So hydrate with whatever you like. I like coconut oil because it doesn't have an offensive fragrances and goes on so nicely.
Re: Breast cream
I dont want to buy expensive stretch mark cream, especially since it isn't proven to work.