[kevan]

I'd implement a good cost attribution strategy before trying a gatekeeping approach. Companies generally have at least semi-functional mechanisms for managing department budgets. Once there's a clear picture how much each service/webapp/product costs to run then they can feed that into the existing budget infra and let things shake out.

Until you know both halves of the ROI calculation it's difficult to focus effort on trimming the right things. e.g. It seems silly for a team to spend $2k/mo on naive/managed solutions for simple things but maybe it's worth it if it helps them avoid hiring another $10k+/mo engineer.