Providing price advantages, especially in the form of bonuses and discounts for early payments with the purpose of keeping and maintaining the steady customers, has become almost a standard part of everyday life for many suppliers. To the customers, these received benefits represent a price reduction for already purchased goods or services. From the tax perspective, providing bonuses and discounts has influence on the determination of the VAT base, respectively on its subsequent adjustment. The suppliers, who are obliged to VAT, usually issue the invoice for the sold goods or provided services in an amount of the full price. In the text of this invoice, they indicate the possibility of discount or bonus, if an early payment is carried out. The exact amount of the bonus or discount, that will have impact on the tax base and the tax itself, is not specifically quantified. After meeting the specified conditions (early payment), the customer is entitled to the price advantage, which should result in the VAT base and tax adjustment. Although the VAT Act requires for this situation, that a subsequent credit note is issued, the suppliers usually do not fulfill this obligation. Many suppliers and customers are also usually unaware, that the same obligation applies even to bonuses and discounts granted to goods and services supplied or provided to or from another EU state, to goods exported or imported as well as goods and services that fall under the so called "reverse-charge" regime.