You can't buy Club Nintendo points.
1) eBay, learn what it is and what you can purchase from it.
3) Pawn shops
You most definitely can buy CN points. Well, maybe you can't, but the option to buy the points is definitely there.
We'l get the demo next week, anyway. The only different thing as far as I know is that the Platinum demo is unlimited use while the next weeker demo is 30 plays.Either way, the only way to to get the demo this early is if you were a Platinum member for Club Nintendo this past year from July 1st 2013-June 30th 2014. If you didn't make the Platinum status, then you are out of luck.