Fresh Young Coconut
To "pick up" one, check the base of the coconut. It should be clear of dark spots and green mold. It should also feel pretty heavy. A good price is under $1.
I use a Chinese cleaver to crack these babies open although I know Whole Foods offer a free coconut cracking service. I don't know the most efficient way, but for me the trick is to imagine a circle you'd like to cut and aiming the bottom corner of the blade, use decisive, steady blows. Don't whack carelessly. Focus and conserve your energy. You know you're not concentrating your energy if it takes more than 20 blows. Oh! And don't forget to peel any plastic or stickers off of it before you start otherwise, you'll the knife might drag that trash into your coconut when you start working into it.
Grab a spoon and a straw, mama. He's ready.