A scale is useful in baking, where proportions matter. For everything else, a tablespoon, a teaspoon and a glass are enough, as long as you know a few equivalents.
A tablespoon is 15 ml. A teaspoon is 5 ml. A standard glass is 200 ml, a bit less than a cup. Everything else follows.
Nothing, once you know those three numbers.
A liquid or a starch slightly over-measured is no problem, it evens out while cooking. A cake is different: if you are not sure of yourself, this is the moment to buy a scale, or to choose a recipe measured with a glass, like the yogurt cake, where the pot is the measure for everything.
Rice by absorption: one glass of rice, one and a half glasses of water, and you weighed nothing.
Very easy