Let's say, you are going to buy a computer. The fast ones with good hardware are expensive. When you lower your budget, the hardware quality is worse, so you will end up with a slower one. You need to find a balance which is best for you in terms of both "speed of the computer" and "money you will spend".
Is there a phrase which describes this decision-making process? I don't mean the decision making based on a list of pros and cons. Here there is only two parameters and you need to find the best combination. I "feel" that there is a phrase, but I forgot -both in English and in Turkish (which is my mother tongue).