Ambitious Google Ads Manager Needed for multiple google ads projects (Belgium)

Google ads manager, that can run our monthly ads campaigns of our agency clients, please provide me a ballpark estimate of the cost (monthly), so we can properly calculate the profitablity - please provide past results... (Budget: €30 - €250 EUR, Jobs: Account Management, Advertising, Digital Marketing, Google Ads, Google Adwords, Google Analytics, Internet Marketing, Marketing Strategy, SEO, Social Media Marketing)