Half-month subscription and lifetime subscription

[Felis]

I wonder if SE could create a subscription plan that only charges half price playing only Monday, Wednesday, Friday and every other Sunday or Tuesday, Thursday, Saturday and every other Sunday for $7/mo or at a reduced price of around $9/mo.

Also, if SE was to allow a one-time charge for lifetime subscription, how much would it be?

half month would be 15 days, not specific weekdays. Maybe $ 7-8 for 15 days?