I have owned Turkish, Armenian, Moroccan, Slavic Macedonian, and Chinese versions of the zounas. I also have several Greek karamoudzes. All are good. The Turkish ones were very reasonable in price and played very well!
The ones you posted links for on ebay look okay. It's just up to you whether you want the approximately 12 inch ones, or longer or shorter. Also you should decide what key you like. Also, the "kaba" instruments are longer and deeper in tone. Do you want higher pitch or lower pitch tone?
Typically, they do not play these with other instruments in traditional folk music. So you really do not have to worry about being in tune with other types of instruments. They are accompanied by the drum (toumpano, tupan, daouli, davul), and are often played in pairs. One plays the melody, while the second plays a drone note or sometimes plays the melody or some riffs of some sort. You might consider buying a matched set so when/if you play with another zourna, the two instruments are matched and in tune.
You will have fun. Listen to and watch lots of videos to help you decide on the sound/size you want.
I'm attaching two photos of the pair I usually use, made for me by a friend here in the USA. THEY ARE THE SAME, just different colors.
I think the kaba zurna is what I'm looking for, but I don't know exactly the key. I guess It could be E or D.
Thank you very much for the help and photos.