Cloud pricing term
What is Public IPv4?
Public IPv4 is a routable address that some providers now price as a separate resource even while it is attached and in use.
The expensive mistake
Assuming an IP address is included because the instance is running. On the recorded AWS t4g.nano, one public IPv4 costs more per month than the base compute. Load balancers and multi-node systems can require several addresses, multiplying the line.
Where it appears on your bill
Look for public IPv4 address, in-use address, idle address, Elastic IP, or network-interface address hours.
Worked example
AWS prices public IPv4 at $0.005/hour. The dated example calculates that as $0.005 x 730 = $3.65/month. The t4g.nano compute price is $3.066, so compute plus one address is $6.716 before EBS and transfer. The IP is 19% more expensive than the compute line.
Example prices checked: