Yeah...many ocarinas are out of tune, or might sound ok on low notes but not high ones. Many of the zelda video game ocarinas are terrible....but they're being sold as more of a fandom thing than a musical instrument sadly.
Songbird Ocarinas are my personal favorite. My two favorite ocarinas are from them, and they're absolutely awesome in sound quality and breath requirements.
Plastic ocarinas mostly don't sound as good..they have an almost toy type sound. In general, clay ocarinas are what I'd recommend. Most ocarinas are clay or plastic, though there are some folks who make them out of wood...but I've never played one of those.
There is one ocarina made out of plastic that has really good reviews, called Night by Noble...and I own one..but condensation from your breath becomes an issue over time which can effect the sound as you play. It's very durable as well, which is nice. The high notes aren't as clean sounding as some other ocarinas though.
http://www.amazon.com/Night-Noble-Plastic-Ocarina-Black/dp/B008WYNVAW/ref=sr_1_5?ie=UTF8&qid=1454870203&sr=8-5&keywords=focalink+ocarina
Focalink ocarinas are also fairly good. They're less expensive than Songbird as well. If you just want to try one out, but want a quality instrument that's worth keeping even after you indulge on a expensive one later....Focalink is the way to go. This is the focalink ocarina I'd recommend:
http://www.amazon.com/Whisper-Strawfire-Masterpiece-Collectible-recommended/dp/B00MJLZIDW/ref=lp_7899678011_1_1?srs=7899678011&ie=UTF8&qid=1454870288&sr=8-1
This is the model I own and the high notes are clean and easy to play, the low notes are light breath and it's a great ocarina to learn on. I still enjoy mine a lot. It stays around $35 on the pricetag.
My personal favorite ocarina is this one:
http://www.songbirdocarina.com/collections/transverse-style-ocarinas/products/sonoro-ocarina-alto-c-in-white-crackle
The low notes have more resonance than the focalink, and sound wonderful. Breath requirements are slightly more than the focalink, but I find the small amount of breath needed on the focalink low notes to be less comfortable. The finish is durable, beautiful and comfortable too. Pricetag is higher though....but I play mine almost daily so the cost was worth it for me.
All the ones I recommended are ones I own. I'm sure there are others that are nice too, in varying price ranges, but I don't feel comfortable recommending anything I've not used personally.
