Ezreal, Prodigy

Ezreal reduces only optional additional costs you choose to pay. These costs use both the word "may" and the exact phrase "as an additional cost."^[356.2.b.1] Accelerate and Repeat are keyworded optional additional costs, so Ezreal reduces them too.^{[805.1.a][820.1.d]}

Ezreal's discount applies to the optional additional cost itself as soon as that cost is added, before discounts that apply to the card's total cost.^{[356.4.c][356.4.d]}

Mandatory additional costs are not optional because they omit "may,"^[356.2.a.1] and payments made while carrying out an effect are not additional costs to play that card. Ezreal does not reduce either kind of payment.