Underwater iPhone case for photos?

I'm looking to start taking underwater photos in the ocean with my iPhone 6. Only up to 15 meters or so. Does anyone have experience doing this? Looking for suggestions on relatively inexpensive cases/bags.
Not looking to spend $100, nor am I trying to ruin my phone.

Waterproof cases for cell phones are good for protection of phone if dropped in water.
Don't expect underwater pictures. Invest in Nikon AW130 or Olympus TG4 if you want good.
Or Nikon S33 if you want not-great but better than iPhone underwater. I think better is worth more if it's your once-in-a-lifetime trip to Candi Dasa, Bali to capture the beautiful fish and coral, but your standards are low.
Do get the case for the iPhone so you won't destroy it near the water's edge when you slip and drop it in the water.

Do a Google search. There are a number of companies who offer such waterproof cases.