What protection actually costs
Plans buy capability. Credit packs buy credits. Here is the whole system.
GPT protection uses no credits, ever, on any plan. Your subscriber's ChatGPT account does that work. Password protection for Skills uses no credits either. Credits pay for one thing only: IP Protection, where your methodology runs on my server and your subscriber gets results back. Results, not your recipe.
The cost depends on the model a Skill uses. Haiku costs 1 credit per run, Sonnet 3, Opus 5. A Skill that runs code needs at least 5 credits available to start.
Credit packs never expire: 1,000 for $39, 2,500 for $95, 5,000 for $179, 10,000 for $339. Whatever you buy stays yours until you use it.
A worked example. A Skill on Sonnet answering 100 subscriber requests costs 300 credits, about $11.70 at the small-pack rate. If your Skills become part of how your business runs every day, the plans that include monthly credits can make sense. If usage is uneven, packs win, and I will tell you so if you ask.
If you'd rather see it than read it, connect free and run a Skill yourself.