An account spending limit is an overall limit on how much your ad account can spend across all the advertising campaigns that you're running. If you set an account spending limit, delivery of your ads will stop when that limit is reached to help ensure that you don't pay more for ads than you want to. This limit is optional, but it can help you control how much you're spending on Facebook ads.

Bear in mind that an account spending limit doesn't automatically reset after a certain amount of time (such as at the end of the month). To continue advertising after you've reached your limit, you can reset the amount spent towards your limit to £0 in your payment settings.

Learn more about using an account spending limit.

* Nguồn: Facebook