It's no secret that Genshin Impact's gacha system is designed to make you want to spend money. You absolutely don't need to do this, though. Since launch, I've been enjoying the game without spending a dime (I should also say I'm not part of any of miHoYo's content creator programs that deal out free currency to content creators).
I've managed to do this all while building out a roster with all the characters I want. How, you might ask? Well, the short answer is math, a pessimistic attitude, and discerning taste. You can also read on below to understand exactly what I mean by this.