Personally, I would never use a snorkel from a rental or "equipment supplied" situation. We purchased our equipment from our local dive shop and it's well worth the investment. You'll have equipment that you're comfortable with, familiar with, and eventually experienced with. As for anti-fogging agents, I'd suggest using only the ones made for dive masks. Those made for automotive purposes can have nasty side effects on the equipment AND your face, you only get one set of eyes.