You can manage your spend by viewing your monthly spend, setting spend limits and stopping your ads.
View your monthly spend to keep track of where and how your budget is being spent.
Click Ads in the top-left corner
Set daily or lifetime spend limits at the campaign level to guard against overspending.
Pause your campaigns, ad groups or ads at any time in Ads Manager to stop accruing costs.
Click Ads in the top-left corner, then click Reporting
If you’re running a campaign with multiple ad groups, pausing one of those ad groups will stop running all the ads within that ad group, but won't impact the other ad groups in that campaign. If you stop running a campaign, you’ll pause all the ad groups within it.