Microsoft has enabled the ability to users to purchase licensing for some of their power apps without administrative approval. This isn’t supposed to be an option for K12 but when I checked our domain, all products were enabled for self-service purchases.
Import-Module -Name MSCommerce
Connect-MSCommerce
Get-MSCommercePolicy -PolicyId AllowSelfServicePurchase
Get-MSCommerceProductPolicies -PolicyId AllowSelfServicePurchase
# To disable the products, you will need to pass each productId into the update cmdlet
# Example uses the id for Power Automate. Repeat with each service.
Update-MSCommerceProductPolicy -PolicyId AllowSelfServicePurchase -ProductId CFQ7TTC0KP0N -Enabled $False