\"30% sticker for cars\" means that if the total price of a car is 100%, then you need to pay only 30% of the total price. This is usually used in marketing and advertising, where a seller will offer a discount on the listed price. For example, if the sticker price of a car is $20,000 and there is a 30% discount, you would only have to pay $14,000 (30/100 * 20,000).