Document credit packs and per-member reset dates

getting-started.md

@@ -30,6 +30,7 @@ account. Click it and create your login.
 - **Private AI chat** through the co-op's shared gateway.
 - **API access** for your own tools and projects (see [API access](api-access.md)).
 - **A monthly usage allowance** of $15 of credit, shared between chat and API.
+- **Credit packs** — buy extra non-expiring credits when you need more.
 - **A voice in governance** — how the project is run and where it goes next.
 
 ## 2. Use the chat
@@ -68,13 +69,33 @@ documentation, and design. See [Infrastructure](infrastructure.md) for the map
 and the "Contributing" section for how to propose changes through
 [git.inference.coop](https://git.inference.coop).
 
-## Your allowance
+## Your allowance and credits
 
 Membership includes **$15 of usage credit each month**, shared between chat and
 API. It's a starting value, not a hard rule:
 
+- The allowance resets each month on your personal billing date (the day your
+  membership payment recurs) — not on a fixed calendar day.
 - The allowance can be adjusted per member — contact info@inference.coop.
-- When it's exhausted, requests pause until the next cycle.
+
+### Need more than the allowance?
+
+Members can buy **credit packs** — non-expiring credits that kick in
+automatically when your monthly allowance runs out:
+
+- Credits **never expire**. Unused credits carry over month to month.
+- They're drawn only after the monthly allowance is exhausted, so your
+  allowance always gets used first.
+- Buy a credit pack on our
+  [Open Collective page](https://opencollective.com/inference-cooperative/contribute)
+  (choose the "Credit pack" option). Credits are applied to your account
+  automatically — usually within minutes.
+- Credit packs are for members. If you buy one before joining, we'll hold it
+  and it will be applied to your account when you join (or refunded if you
+  prefer — just email info@inference.coop).
+
+You can see both buckets — allowance left this cycle and non-expiring credits —
+on the [Member Dashboard](https://dashboard.inference.coop).
 
 ## Need help?