Simple, foundational champions (e.g., Garen, Annie, Amumu ). Great for learning mechanics.

Each level rewards a Champion Capsule containing champion shards.

If you tell me your (like "aggressive" or "supportive") or which lane you like, I can suggest which champions are currently the best "buy" for your rank.

Riot often sells roles-specific bundles (Top, Jungle, etc.) for a very low RP cost, offering 3+ champions and a skin.