Auto is a free model; however, it’s going to start costing tokens starting when your subscription renews after 9/15. It is a decent model and great for boilerplate. If you want to be grandfathered into unlimited Auto for a year, you have to get an annual subscription before 9/15. That way your renewal date is a year from now and that will lock in unlimited Auto. More Info: Update to Teams and Auto Pricing
Gpt-5-mini also appears to be free and not count towards monthly usage limits. I wonder if that model would work for you even though you have hit your limit.