Add pricing faq for PostHog AI credits

contents/docs/posthog-ai/pricing-faq.mdx

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+AI features in PostHog consume **AI credits**. Each time you interact with an AI-powered feature – like asking PostHog to write SQL, summarize data, or analyze sessions – credits are used based on the effort required to complete your request.
+
+This means you pay for what you actually use. There’s no fixed subscription and every organization has a free tier worth $25 (2,500 credits) to explore PostHog AI's features.
+
+## What consumes AI credits
+
+AI credits are consumed whenever PostHog performs intelligent work for you.  
+You’ll spot these features by the ✨ icon or when using the in-app chat.
+
+Examples include:
+- Searching for session recordings in natural language  
+- Summarizing experiment results  
+- Writing or debugging SQL with AI  
+
+## What doesn't consume credits
+
+Getting help on how to use PostHog never costs credits. All AI features still in beta are also free to use — as of **Oct 31**, that includes **session summaries** and **deep research**.
+
+## How credit usage works
+
+AI credits are based on the **underlying token costs**, which reflect the effort required to complete your request.
+
+- Simple queries like "What were my daily active users in October?" use very few tokens, and therefore very few credits.
+- More complex tasks like analyzing hundreds of session recordings or rewriting a SQL query multiple times use more tokens and consume more credits.  
+
+While exact usage varies, credit consumption usually scales with complexity – more advanced tasks cost more but can deliver deeper insights and time savings. You’ll always see **real-time cost information** while using AI features.
+
+PostHog automatically selects the most efficient model for each AI feature. We apply a simple, consistent 20% markup over the underlying LLM provider’s cost. For example, 1 PostHog AI credit equals $0.008333 of raw inference, and 1,000 credits cost $10.
+
+| Example interaction | Estimated credit cost |
+| --- | --- |
+| "What are my daily active users in October?" | coming soon |
+| "Show me session recordings for this organization_id" | coming soon |
+| "Can you help me write a SQL query that…" | coming soon |
+
+---
+
+### Track your AI credit usage
+
+Stay on top of your AI credit spend in real time:
+
+1. Type [`/usage`](https://app.posthog.com/#panel=max:!/usage) in chat to see the current cost of your conversation  
+2. Check the [**Billing overview**](https://app.posthog.com/organization/billing/overview) & [**Billing usage**](https://app.posthog.com/organization/billing/usage) pages to view your total monthly consumption  
+3. (Coming soon) A dashboard showing which AI features use the most credits  
+
+> 💡 Credit data may take up to 24 hours to appear on the billing & usage page.
+
+---
+
+### Control your AI credit spend
+
+You’re always in control of your AI credit usage:
+- **Real-time tracking:** See costs as you go  
+- **Custom billing limit:** Set hard caps to prevent overspending
+- **Default billing limit:** PostHog sets a default $250 billing limit so you don't accidentally rack up costs without a ceiling 
+- **Usage alerts:** Get notified when you hit key thresholds