PirefyroYou should look up reviews of these cubes on YouTube to get a more complete understanding of the puzzles. From what I've seen, the Gans 3x3 is a very good cube. For the 2x2, Moyu is a well-known brand, so I would expect high quality there. I don't want to say anything about the YJ 4x4 because I'm not that familiar with the company.
PirefyroEvery one of these cubes are great. But I would not recommend you these ones for "first cube", It's better to start with some crappy 3x3, and then move to something good.
PirefyroOn the contrary, I would highly suggest starting with higher end cubes like this. What's the point in spending money on a 3x3 only to spend more on another better one in the future, especially with a deal like this? If you think you are going to stick through learning to solve them, these are all great cubes! If you're unsure, rather than a "crappy cube" you should check out the Guanlong 3x3! You can get it for like $1 on some sites, and it's still better quality than any Rubiks brand cube.