If you are looking to buy ocarinas, you have come to the right tutorial. Here are some tips.
Step 1: Start Small
Don't go too high in the prices, I'd recommend to start with 10 to 30 dollar ocarina. Here is a link for an ocarina seller: http://aceocarinas.weebly.com/
Start with 4 to 6 holes just in case you won't like playing the ocarina.
Step 2: Continue Buying Better Ocarinas
If you like playing ocarinas, then continue to another website. If you like Ace Ocarina's style, then continue buying from him. If not, move on to STL Ocarinas: www.stlocarina.com
Step 3: Move From 4-6 to 12
12 hole ocarinas are hard to learn the fingering, but easier to master. So spend some time fidgeting with the 12 hole ocarina until you get used to the fingering. Try doing the Jeopardy thinking theme, or maybe Stone Tower Temple theme. You will get used to the fingering if you mess around with it instead of touching an playing with it once every week.
Step 4: Extra Tips for Sound
If you or someone in your house has hearing problems or sensitive hearing, stay away from the soprano and alto ocarinas. Soprano and altos can shriek if blown too hard, and can permanently damage hearing. So stick with tenor or bass.
Step 5: 12 Hole to Double
Doubles have 2 chambers. It will take a while to learn, but you will master it sooner or later. It is a smart idea to purchase a plastic one first to see if you like to play doubles. STL Ocarina sells plastic doubles.
Step 6: If You Still Don't Understand...
If you still don't understand, then watch the video at the end.