Saw this promotion today, valid from the beginning of September to the end of October. Asus offer $20-$50 prepaid VISA cards by redemption with proof of purchase. Some examples of prices would be:
VE258Q - $279 (after $20 cash-back) from Computer Alliance
VE278Q - $358 (after $30 cash-back) from MSY
PA246Q - $499 (after $50 cash-back) from Digital Star
I hate this kind of Visa cash back, last time I ended up forgot about the $10 visa card and expired.