Wet AND dry measuring cups
Ballpark price: $15 AND $14
Wet measuring cups (typically used for liquid ingredients) are made of transparent material and have a spout for easy visibility and pouring, whereas dry measuring cups (typically used for flour, sugar, or any other dry ingredients) are perfectly flat across the rim so you can level things off with ease. Go for glass and stainless steel respectively, because they’ll last longer and are less likely to end up disfigured, and thus inaccurate, from normal wear and tear.
While, technically, they both hold the same volume, your recipes will be far more precise if you invest in a set for both liquids and solids.