OpenAI:

With this launch, ChatGPT now offers three subscription tiers globally:

• ChatGPT Go at $8 USD/month
• ChatGPT Plus at $20 USD/month
• ChatGPT Pro at $200 USD/month

And perhaps the bigger news:

We plan to begin testing ads in the free tier and ChatGPT Go in the US soon. Ads support our commitment to making AI accessible to everyone by helping us keep ChatGPT available at free and affordable price points.

Their pricing page has a comparison chart showing the differences in their four consumer tiers (free, Go, Plus, Pro). Screenshot, for posterity. The big difference that will keep me on the $20/month Plus plan for now is that the Go plan doesn’t have access to the Thinking model.