While you may think you're getting better protection from a pricey sunscreen, how much your sunscreen costs doesn't really have much to do with how well or how poorly it protects your skin from UV rays.
A 2012 study conducted by Consumer Reports finds that it's actually the inexpensive sunscreens that are most likely to give you the most effective UV protection without issues of stickiness or greasiness. For example, the most expensive sunscreen tested sells at just shy of $19 per ounce and scored less effective than products selling for less than one dollar per ounce (in fact as little as $0.59 per ounce). What's the lesson here? When you find a sunscreen you like, stick with it. The best sun protection is one that you use, not the one that has the highest price tag.