You will probably find a piano key style melodica easier to play as a starter instrument. The inexpensive brands such as Swan are all made in China, and among those there does not seem to be much difference. I suggest starting with an inexpensive 32 key model. Serious music can be played on it, so no need to think of it as a toy. Then, if you get into it and are having some success, think about moving up to a more expensive model with the number of keys you want. A lot of us recommend models such as the Suzuki M-32C or M-37C or the Yamaha P-32D or E or P-37D. Those are not made in China, but the cheaper Chinese models are fine to begin with.
It is hard to predict whether an older button model will have good sound and play well.