If the question ever comes up when collecting "do I wait for payday?" -- always wait for payday. It can be hard sometimes, but never let the hype of collecting get in the way of rent and groceries.
That being said I don't see the deluxe set selling out anytime soon, so you should be safe.
If I had to wait for payday to pre-order, let alone pay for an entire figure, I wouldn't be in the business of collecting.