Open Spending
On Model providers, Limits, Spending limits points at the Spending page. Monthly and daily limits are set there.
Open Connections, then Model providers, then the Limits tab.
Spending limits
The section Spending limits says The company's spending limits have their own page. Follow Open Spending ›. That opens Settings › Spending, at /settings/spending. The heading is Spending.
Monthly and daily limits, what has been spent, and Save limits are on that page, not on Models or Add models. See Set the company's spending limits.