Blue Essence is the standard "earned" currency. You cannot buy BE directly; you accumulate it through:
💡 Always try champions during the Free-to-Play Rotation before spending your hard-earned Blue Essence.
RP is the premium currency. Buying champions with RP is generally considered "inefficient" by veteran players unless there is a massive sale, as RP is better spent on cosmetic skins that cannot be earned through standard play. 💎 Maximizing Value: The "Shard" Strategy
Using a champion shard to unlock a character costs 40% less Blue Essence than buying them directly from the store.