If you buy cheaply through resale you will need to pay cash, either by saving it up or by organising financing yourself independently of the transaction. The best way to do it is to save up the cash.
If you buy direct from Disney they will give you a payment plan in the form of a very high interest rate loan. You will pay much more for the points but you will be able to pay monthly.
Personally I would start with a small contract pay cash for it and then save up again until i could afford more points. however, i appreciate that is hard to do in todays market with significant demand for low point contracts.
