Took me a while to get the hang of this low cost sax. Like most beginners, it was difficult to get even a sound out of this horn. Sounded mostly like a cow's f*rt!
After practising correct mouth and hand positions and lip technique, I finally was able to get some usable melodies out of this saxophone. Took a few moths.
Now what I had to do: Of course I had to buy 2,5 - 3 strength reeds. (The sax came only with one reed, soon chewed to pulp.) Also a good cleaning snake helped me to get rid of all the organic goo that invariably infests the innards. But the most important tip was (and is) to buy a good quality mouth piece. Well, a mouth piece might cost as much as the STS-75 sax, but I do not think you have to go that far. But still invest, like I did, some 40-50 euros on a decent mouth piece and you are good to go!
With my medium-sized mouth piece and good medium strength reeds I can practise easily and even record some bits and pieces in my home studio. (Simple stuff, mostly two or three tone riffs, which I used to play on the keyboard.) The Startone STS-75 is good enough for me for the foreeable future. It might not be the most mellifluous of instruments, the sound being a bit metallic, but it works with rock music (think G. Thorogood & Delaware Destroyers!).