Most currently available melodica brands have their melodicas made in China, Jessica. I do not own a Stagg and have never played one, but it has every appearance in photos of being what I will call “the cheap generic Chinese melodica.” Cheapness in this sense is not always reflected in the price. It is a matter of quality of design, construction, and reeds. You might find one of these instruments to be very enjoyable to play and you might really like the sound. But it will be markedly inferior to a Yamaha (now made in Indonesia to Yamaha specifications) or a high end Suzuki (one of the ones with a metal tray, such as the M-32C, made in Japan). Cheaper Suzukis are now made in China, as are most, if not all, Hohners.
To some extent, the difference in build quality is reflected in the weight of the melodica, and it’s even more evident when you take melodicas apart and see what’s inside. If you look at the How to Tune a Melodica tutorial here, what you see is the insides of a Yamaha P-32D.
There’s no harm in starting out with a cheaper melodica, though. It’s a small investment, and you can always upgrade later. But in my opinion the Yamaha is more than worth the difference in price.