If your $1/day Meta campaign has only spent $3 over 8 days, it's likely due to limited delivery caused by either a too-low daily budget, narrow audience targeting, or your optimization goal being too ambitious for the budget.
Meta's algorithm may hold back spend if it doesn't see a good chance of hitting your goal (like purchases) with such a low budget.
To improve performance, consider increasing your daily budget slightly (to around $3–$5/day), broadening your targeting, and optimizing for higher-funnel actions like link clicks or landing page views instead of conversions. This can help Meta gather enough data to exit the learning phase and spend more consistently.