For users without a significant amount of data of using Facebook ads, it's tricky defining how much budget you require. It would technically be 50-100X the cost of the desired action (link click, lead, likes, engagements, sales etc)


However, the minimum budget to avail the service is 25/day (min. budget for optimisation of CPC per campaign) and recommended starting budget is USD75-125/day per campaign.


As per Facebook: Your ad set needs about 50 conversions per week for our delivery system to learn who it's best to show your ads to, and more conversions are better.


Learn More - https://www.facebook.com/business/help/1730527393892983