Hi,
Pricing for Public IP addresses in Azure can vary based on the SKU chosen by the customer – Basic or Standard and the type of IP address – dynamic or static. The table below summarizes the pricing structure for Public IPs.
The prices are well documented in the following doc: https://azure.microsoft.com/en-us/pricing/details/ip-addresses/?WT.mc_id=DP-MVP-5001699 Regarding the amount of public IP that you can have
Default limits for Public IP addresses vary by offer category type, such as Free Trial, Pay-As-You-Go, CSP. For example, the default for Enterprise Agreement subscriptions is 1000.
And here is the full information: https://learn.microsoft.com/azure/azure-resource-manager/management/azure-subscription-service-limits?toc=%2Fazure%2Fvirtual-network%2Ftoc.json&WT.mc_id=DP-MVP-5001699#publicip-address