Recommend an oil-free & natural sunscreen for the face?

I am currently using Boscia's oil-free moisture with SPF 15, but it is very expensive at about $36 at Sephora and it comes in a rather small tube. Can anyone recommend something similar that might be somewhat cheaper? I'm looking for oil-free, specified for face to avoid breakouts, and natural (no parabens, harsh chemicals, etc.) Apparently it is impossible to find something that isn't harmful to your face in one way or another and can also protect you from the fun.