When buying digital game content online, how do promo codes usually affect pricing and delivery? What should users check to make sure the discount is applied correctly and does not cause issues with confirmation or access later on?

When buying digital game content online, how do promo codes usually affect pricing and delivery? What should users check to make sure the discount is applied correctly and does not cause issues with confirmation or access later on?

When buying digital game content online, how do promo codes usually affect pricing and delivery? What should users check to make sure the discount is applied correctly and does not cause issues with confirmation or access later on?