Plan the give-away, size your coupon codes safely, and time your reorder so you don't stock out mid-launch.
Coupon-safety (always do this): set every launch code to PREFERENTIAL + single-use. Otherwise a buyer can stack your launch discount with a clippable coupon and check out at 100% off — wiping your whole inventory for free. Issue ~20% more codes than sales you want (people grab codes and don't redeem).
Birthing-window readiness — all GREEN before inventory lands