it is exactly the same concept as the pricing you see everyday in a supermarket
B*ll*cks, to be as polite as I can.
No supermarket has ever offered me a discount if I lend them a year's grocery money (which is the same order of magnitude as paying for a PPL up front). If they did I wouldn't take the offer, I'd look around for a supermarket less likely to go bust.
The equivalent of the supermarket's offer would be the emails I get from my club from time to time: "there's spare capacity today, come and fly this afternoon for a 5% discount". Which I would be paying for
after flying, in the normal, and sane, fashion.