Practical budgeting for a car must include both the loan payment and recurring ownership costs. Imagine a $20,000 car financed at 4% APR for 60 months, plus typical monthly costs: insurance $120, maintenance $50, registration $10. To estimate how much to set aside each month, add the loan payment to these recurring items. Doing rough-but-accurate arithmetic before you shop helps you choose models and loan terms that fit your budget without surprises. This is a hands-on calculation many first-time buyers will perform to build a monthly auto budget. (Numbers in the question are examples.)