Most devs overpay for Claude API by 3-16x. RPG Materia teaches you to fix that — through 5 gamified missions, real code, and a GRIM owl who judges your choices. • M1: Token audit (where your money actually goes) • M2: Prompt caching (90% off repeated context) • M3: Model routing (Haiku is 12x cheaper) • M4: Output control (stop paying for silence) • M5: Batch API (async = 50% off) Free to play. Pay what you want. Certificate included.