Buying a new car is a huge financial decision that requires some thoughtful and responsible planning to ensure you’ll be able to afford it. If you’re buying a cheap, used car, you might be able to pay cash, but pretty much everyone who purchases a new vehicle will need to take out a loan of some sort. That’s hardly a surprise given the rising cost of new cars: in the first quarter of 2018, the average new-car loan was for $31,455, according to data from Experian Automotive.Financing a car isn’t always the right option. If you can afford to pay cash, even for a new vehicle, without putting yourself in a financial strain, it could make sense to do so. But with low interest rates, you may be better off putting that money into an interest-bearing account instead. Of course, knowing a car’s full list price isn’t necessarily that helpful to figuring out whether you can afford it. Most of us plan our budgets monthly and thus want to know how much the payments for a new car will cost each month. Here are some guidelines to help you find a reasonable figure.Setting a monthly numberIt might seem obvious, but the…