...placed in a zip lock bag.
All cameras can probably withstand a bit of rain or splashing, but there are no "waterproof" cameras under $100. If you get a camera wet enough to where water (especially salt water) penetrates the electronics and what not, there is no guarantee it will continue to function.
Of the cameras that are rated for water resistance, the least expensive is the Olympus Stylus Tough 3000, about $150.
Want a camera that can withstand moisture while on a boat, not for underwater pictures that sells for less than $100.

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