There are indeed a whole lot of classic Mario games on the VC.
Mario Bros - 500 points
Super Mario Bros - 500 points
Super Mario Bros 2 - 500 points
Super Mario Bros 3 - 500 points
Super Mario Bros: The Lost levels - 600 points
Super Mario World - 800 points
Super Mario RPG Legend of the Seven Stars - 800 points
Super Mario Kart - 800 points
Mario Bros 64 - 1000 points
Mario Kart 64 - 1000 points
Paper Mario - 1000 points
Mario Golf - 1000 points
I own them all apart from Mario RPG, Mario Golf and Mario Kart.
As Shadow*91 said, you would need a Wii Classic Controller ($25) to play any of the SNES or N64 games. You can also use a Gamecube controller but the button layout isn't ideal for SNES games.
Wii points can be bought in a store, a 2000 point card costs $20 - $25. You can also buy them directly from the Wii shop channel using a credit card.