nope. not true.

you do get achievement points, see in the thing in my sig, where it has the G? thats my gamerscore. which depending on the achievements in game, depends on how many points you get from it.

for demos of games on the arcades, you get em for free.

the full games cost between 400 and 800 microsoft points, of which you can buy through live using a credit card, or buying a card in stores.