How does Cobiro manage my daily budget for the created campaigns?

Cobiro uses the daily budget you have set during the setup of your Google Search and Shopping Ads. It is the highest amount that you feel comfortable spending per day on your ads.

Depending on your ad performance and the search traffic, the total daily cost of your campaigns can be up to twice your daily budget. This means your campaign is spending more of your daily budget on days with higher search traffic and less on days with lower traffic. 

However, with all Google Ads campaigns you won't be charged more than your average daily budget multiplied by the average number of days in a month (30.4).

More information about this can be found here.