LLM pricing · Compare

GPT-6 luna vs GPT-6 sol pricing (November 2026)

In short: GPT-6 luna is 20× cheaper than GPT-6 sol per chat message: $0.00035 vs $0.0070 for a typical chat turn (1,500 tokens in, 400 out). On a $9.99 plan, a user can send about 24,261 messages a month on GPT-6 luna before they cost more than they pay, versus 1,213 on GPT-6 sol.

Price per million tokens

GPT-6 lunaGPT-6 sol
ProviderOpenAIOpenAI
Input$0.1$2
Cached input$0.01$0.2
Output$0.5$10
Long promptsover 272,000 tokens: $0.2 in, $0.75 outover 272,000 tokens: $4 in, $15 out

Cost per message and per user

GPT-6 lunaGPT-6 sol
Per message$0.00035$0.0070
Per message, prompt 2/3 cached$0.00026$0.0052
Light user (30 msgs/mo)$0.0105$0.210
Typical user (300 msgs/mo)$0.105$2.10
Heavy user (3,000 msgs/mo)$1.05$21.00
Break-even on $9.9924,261 msgs/mo1,213 msgs/mo

Red: the user costs more in AI than the $8.49 you keep from a $9.99 plan after a 15% store fee.

Which to use

Price is only half of it: pick the cheapest model that gives answers your users accept. Many apps route most traffic to the cheaper model and send only hard requests, or only paying users, to the stronger one. Whatever the mix, the number that decides your margin is cost per user, because a few heavy users usually drive most of the bill.

Try your own numbers

Cost per message
$0.00035
AI cost per user / month
$0.11
Margin per user / month
$8.39
Break-even messages / month
24,261

List prices, standard tier, prompts under the long-context threshold. Averages hide your heaviest users: FiscaLLM shows this per real user.

Track the real cost of each user

FiscaLLM prices every OpenAI call with these rates, per user, and sets it next to what that user paid through RevenueCat, Stripe or a CSV. You see which users and which model lose you money. Free and open source. See the demo.

Questions

Is GPT-6 luna or GPT-6 sol cheaper?

GPT-6 luna is 20× cheaper than GPT-6 sol per chat message: $0.00035 vs $0.0070 for a 1,500-token prompt and a 400-token reply, at list prices.

How many messages can a $9.99 subscriber send on each?

About 24,261 a month on GPT-6 luna and 1,213 on GPT-6 sol, before AI cost uses up what you keep after a 15% store fee.

Can I use both?

Yes. A common pattern is the cheaper model for most traffic and the stronger one for hard requests or paying users. Track cost per user to see whether the mix pays off.

List prices, standard tier. Batch, priority and regional pricing differ; check each provider for the latest.