renting equipment from places so we finally bought our own from a dive shop and then got scuba certified. Owning your own is SO much better! You can make sure they fit right, dont leak and NO ONE else's mouth or spit has been on it! I would imagine you could find a mask and snorkel at ANY sporting goods store in your area or at a Costco,
Walmart, Target. They all carry them year round. Maybe not a huge selection but even in land locked freezing cold snowy Utah we have them at all of those stores. We bought our kids Mask, Snorkel and Fins at Galyans here in Utah but all of our Walmarts and such carry them. We just bought a replacement snorkel for DS's set last weekend in the snow.
If you do buy your own to make sure your mask fits right:
Put the mask on your face WITHOUT the strap on the back of your head. Then breathe in through your nose and hold your breath. If the mask stays on your face and you cant hear air it is a good fit! If it starts to fall while holding your breath or you can hear air it will leak on you in the water!! We've bought 2 masks now for scuba (gone up a level) and that is the #1 way to tell if it fits!
Also if you wear ANY mask while snorkeling and it fogs up take it off, spit into it with spit from your mouth, rub it into the mask lens all around the corners and such and then rinse. It isnt an awesome defogger but it will help in a pinch!
Also if you buy your own snorkel it is better in our opinion to buy ones that have a purge valve in them! Meaning that if water goes down in the snorkel it wont go in your mouth it will go into a filter and back into the ocean.
We would never ever ever rent a mask and snorkel again but then we are big divers. If you dont think you will ever snorkel or use them again then it probably isnt that wise but if you plan to snorkel twice on your cruise or go on another cruise it would be worth it to look into it. You can usually get a mask and snorkel with fins sometimes for 40 dollars or less....
JMO
Heidi