Bonuses attach to any rate tier:
View milestones: e.g. $2,000 at 1M campaign views, $3,000 at 5M. Ladders can stack additively (hit both, pay $5,000) or "highest wins" (only the top rung pays).
Per-post milestones: reward individual posts that break out.
Post-count bonuses: reward volume, one-shot or recurring weekly/monthly.
Bonuses are a clean way to keep base rates modest while rewarding the outcomes you actually want.