fix(ipam): add info on ip billing (#5192)

* fix(ipam): add info on ip billing

* Update pages/ipam/reference-content/understanding-ip-billing.mdx

Co-authored-by: Jessica <[email protected]>

* Update pages/ipam/reference-content/understanding-ip-billing.mdx

* fix(ipam): clarify billing is an example

---------

Co-authored-by: Jessica <[email protected]>

Author: RoRoJ

menu/navigation.json

@@ -3993,6 +3993,10 @@
                   {
                     "label": "IPV6 and the Scaleway ecosystem",
                     "slug": "ipv6"
+                  },
+                  {
+                    "label": "Understanding billing for IP addresses",
+                    "slug": "understanding-ip-billing"
                   }
                 ],
                 "label": "Additional Content",

pages/ipam/reference-content/understanding-ip-billing.mdx

@@ -0,0 +1,52 @@
+---
+meta:
+  title: Understanding billing for Scaleway IP addresses
+  description: Learn how Scaleway bills flexible (public), and private IP addresses. Get help to understand your bill, with common questions answered.
+content:
+  h1: Understanding billing for Scaleway IP addresses
+  paragraph: Learn how Scaleway bills flexible (public), and private IP addresses. Get help to understand your bill, with common questions answered.
+tags: flexible-ip billing private-ip reserved-ip
+dates:
+  validation: 2025-06-26
+  posted: 2025-06-26
+categories:
+  - network
+---
+
+This document aims to help you understand how Scaleway bills **public** and **private** IP addresses.
+
+## Public IP addresses - flexible IPs
+
+Public connectivity for **Instances**, **Elastic Metal**, **Load Balancers** and **Public Gateways** is facilitated by a [flexible IP address](/ipam/reference-content/public-connectivity-best-practices/#flexible-ip-addresses-definition). A flexible IP address is a public IP address that you can attach and detach from the resource at will.
+
+- Flexible IP addresses are billed separately to the resources they are attached to.
+- Hourly rates for different types of flexible IP addresses can be found on the [Scaleway pricing page](https://www.scaleway.com/en/pricing/network/#additional-ip). Note that while flexible IPv4 addresses are generally billable, flexible IPv6 addresses are often free.
+- Hourly billing for a flexible IP begins when you reserve it and ends when you delete it from your account. It is billed even if it is not attached to a resource.
+- Prices are rounded to a minimum amount of €0.01 on a per-IP basis. This means that if you keep a given flexible IP for only a short duration (less than a day), its billing may be higher than you expect. See example below.
+
+<Message type="tip">
+
+**Rounding of hourly billing for flexible IP addresses**
+<br />
+The following scenario exemplifies the rounding used.
+Note that you should always check the [Scaleway pricing page](https://www.scaleway.com/en/pricing/network/#additional-ip) for the most up-to-date hourly rates.
+<br />
+- A flexible IPv4 address is billed, for example, at €0.004 per hour
+- You create **three** flexible IP addresses at 3pm and delete them all **1 hour** later at 4pm
+- Cost incurred per IP address is therefore `0.0004 x 1 = €0.0004`
+- As this does not meet the minimum billable amount of €0.01, the cost for each IP is rounded to `€0.01`
+- You will therefore be charged `3 x 0.01 = €0.03`
+</Message>
+
+## Other types of public IP
+
+Depending on the resource type, it may have possibilities for other types of public IP other than a flexible IP. Billing will therefore be different: many of these types of IP are free (e.g. public endpoints for Managed Databases).
+
+For the most up-to-date information on hourly rates, always check the [pricing page](https://www.scaleway.com/en/pricing/) or the **Estimated cost calculator** that displays in the Scaleway console whenever you create a resource.
+
+## Private IP addresses
+
+Whenever you attach a resource to a [Private Network](/vpc/how-to/attach-resources-to-pn/), it gets a private IPv4 and/or IPv6 address on that network.
+
+Private IP addresses at Scaleway are always free of charge. This applies to both auto-allocated and [IPAM-reserved](/ipam/how-to/reserve-ip/) private IPs.
+