What To Look For
Look for a higher quality silicon skirt around the edge of your mask. The most important element of a mask is the fit and a silicon skirt is more likely to conform well to your face and maintain the ability to do so. When checking out a mask, first press it gently against your face. It should quickly form a complete seal and hold reasonably well. Make sure the nose box is not too large, but also that it doesn't make contact with your nose. Also, pick a strap that spreads the tension over the back of your head, preferably one with two segments of strap, rather than a single band.
Common Pitfalls
An improper fit can lead to a mask that leaks water. There are two basic types of masks, single and double pane. Single pane has a single sheet of glass through which you can see while double pane is divided into two separate lenses. Make sure you pick the one that gives you the best line of sight. While peripheral vision is always reduced in a mask, side panels can sometimes alleviate the issue. Avoid the common mistakes of poor fit and limited sight.
Where To Buy
Masks need to be tried on in person, preferably in a specialty shop. In a dive shop they will be able to guide you in ensuring that you can properly adjust pressure and fit a new mask. While you may pay a little extra, it's important that your mask is attuned to the specifics of your face.
Cost
While masks can be found for cheaper, a good base price to expect is $30. Once prices start getting over $80 you are typically paying for more advanced features like anti-reflective coatings.
Comparison Shopping
There are a number of online dive shops that occasionally offer lower prices than normal retail locations. However, you shouldn't purchase from an online dealer unless you are absolutely sure of the fit. The easiest way to save money is to buy a mask before you arrive at your snorkeling location. High mark-ups in tourist areas should be expected.
Accessories
The two accessories most necessary to maintaining your mask is anti-fog solution and an extra strap. Sea water is corrosive and will eventually break down the strap that came with your mask. Don't let a broken strap ruin your snorkeling session. Another good idea is a lined stuff sack or case for your mask. Nothing is more annoying than a scratch always in your line of sight.
Insider Tips
Many snorkelers and divers swear by spit when it comes to keeping you mask defogged. Spit in your mask, rub it around, then do a quick rinse to remove the excess.
