Hi Reginald,
Thank you for reaching out.
Could you confirm if you are pertaining to the Display campaign? It is not possible to set a budget on the ad level. If you are pertaining to the Display campaign, then this campaign type can use shared budgets. You can refer to this
guide on how to share the budget.
Let me know if you have further clarifications.
Regards,
Dannison
Google Ads API Team

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