So I am doing FB workouts for a while now and I am feeling that I want to buy dumbells to upgrade my game. Untill now I used waterbottles. Since I am not so familiar with this, I don't really know what kinds to buy. Buying a set of different weights is a bit expensive, but what would you guys recommend? Buy just 2 weights, but then how much is the best? Or buy a set that is a lot more expensive?