Imagine you have two goods: tacos (T) and ramen (R). Your income is $I$, and prices are $P_T$ and $P_R$. Your budget constraint is: $P_T \times T + P_R \times R = I$. Simple, right? It just says: don’t spend more than you have—unless you like eating instant noodles after bills.
Now, you want to get the most “utils” (economist-speak for joy) from each dollar. That means you’ll eat tacos until the marginal utility per dollar of a taco equals that of ramen. Seriously, economists think about this while ordering pizza.
