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 500USD (min. budget for optimisation of CPC per campaign) and recommended is 2000USD 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.