billing cycles vs installments

[yotkla]

Subscription vs Recurring vs Installment

Hi, I offer a membership where my customer chooses the duration 3, 6 or 12 months. The longer their membership the less the monthly fee.

As an example...

If they choose to join for 3 months, the cost is of the membership is $3000. They will pay $1000 per month. 

If they choose to join for 1 year the cost of the membership is $9000. They will pay $750 per month. ($750x12 = $9000)

To get the discount, they are committing for the full membership cost. They can't signup for the 1 year and then cancel after 3 months.

What is the best way to set this up in paypal? Subscription vs Recurring vs Installment? Something else?