On July 30, OpenAI cut the price of GPT-5.6 Luna by 80%. Not a typo: $1.00/$6.00 per million tokens became $0.20/$1.20. Terra dropped 20% to $2/$12. The flagship Sol didn't move.
Meanwhile Anthropic's Sonnet 5 is sitting at an introductory $2/$10 that reverts to $3/$15 on September 1 — three weeks from now. And Alibaba priced Qwen3.8-Max at $2/$6 with $0.25 cached input.
Price is now a strategy weapon, and if you run agents, your bill is suddenly negotiable. Let's do the arithmetic nobody's announcement includes.
The board as of this week
| Model | Input /1M | Output /1M | Notes |
|---|---|---|---|
| GPT-5.6 Luna | $0.20 | $1.20 | was $1/$6 until Jul 30 |
| GPT-5.6 Terra | $2.00 | $12.00 | was $2.50/$15 |
| GPT-5.6 Sol | $5.00 | $30.00 | unchanged |
| Claude Sonnet 5 | $2.00 | $10.00 | $3/$15 after Sep 1 |
| Claude Opus 5 | $5.00 | $25.00 | |
| Qwen3.8-Max | $2.00 | $6.00 | $0.25 cached input |
What that means for a real workload
Take a workload I think is representative of a solo builder running a coding/ops agent daily: 3M input + 300K output tokens per day (agents are input-heavy — context re-reads dominate). Over 30 days that's 90M in / 9M out:
| Model | Monthly cost |
|---|---|
| GPT-5.6 Luna | $28.80 |
| Qwen3.8-Max | $234 |
| Sonnet 5 (intro) | $270 |
| Terra | $288 |
| Sonnet 5 (from Sep 1) | $405 |
| Opus 5 | $675 |
| Sol | $720 |
Two things jump out of that table.
First, the spread between cheapest and priciest is now 25x for the same token volume. A year ago the tiers were maybe 5x apart. The vendors are telling you, loudly, that most agent traffic doesn't need a flagship.
Second, caching changes the ranking. Qwen's $0.25 cached input means that same workload at a realistic 70% cache-hit rate lands around $124/month — agents re-read the same context constantly, so cached-input pricing is worth more to agent builders than headline price. Check your provider's caching discount before comparing base rates; it's where the real money is.
How I'd actually route
The mistake is picking one model. The move is routing by task risk:
- High-volume, low-stakes (classification, extraction, summarizing logs, first-pass triage): Luna at $0.20/$1.20 is close to free. If you're doing this on a flagship, you're donating money.
- The agent's main loop (code edits, multi-step tool use): Sonnet 5 or Terra tier. This is where quality drops actually cost you time.
- Escalation only (gnarly debugging, architecture decisions, final review): Sol or Opus 5, invoked by the cheaper model when it's stuck, not by default.
[PERSONAL TAKE — what you route where in your own product, and one surprising thing your bill taught you.]
The catch nobody prints
An 80% price cut on last quarter's mid-tier is also a signal about where that model sits in the lineup now. Vendors cut prices on tiers they've already beaten internally. You're not getting a discount on the frontier; you're getting the previous frontier at clearance. That's still a great deal — just don't confuse it with generosity.
And mind the reversion dates. Sonnet 5's intro pricing expiring Sep 1 is a 50% jump on both sides of the meter. If your margins depend on intro pricing, you don't have a margin — you have a countdown.
What's your actual monthly spend and split? Genuinely curious what routing setups people have landed on — drop your numbers in the comments
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