As an Aussie it is like second nature to us...our makeup has sunscreen in it. My experience here in Australia is that Sunscreen is a huge ripoff in the sense of marketing...they all do the same thing and are basically the same stuff(compare some labels) with different additives. "Home Brand" sunscreen performs as well as "Commercial Brand" Stuff.
The differences are going to be in smell and texture...
Get a good 50+ sunscreen apply 20 minutes before going outside and re-apply just before going out into the sun, make sure you have a waterproof one if swimming, and ensure you reapply frequently otherwise ensure you limit your time in direct sunlight to a minimum.
As they say here From the Australian Cancer Council
http://www.cancer.org.au/preventing-cancer/sun-protection/preventing-skin-cancer/For best protection, we recommend a combination of sun protection measures:
Slip on some sun-protective clothing that covers as much skin as possible.
Slop on broad spectrum, water resistant SPF30+ (or higher) sunscreen. Put it on 20 minutes before you go outdoors and every two hours afterwards. Sunscreen should never be used to extend the time you spend in the sun.
Slap on a hat – broad brim or legionnaire style to protect your face, head, neck and ears.
Seek shade.
Slide on some sunglasses – make sure they meet Australian Standards.
Edit I probably should have mentioned the high rate of skin cancer in Australia and without these guideline the numbers would be horrific..