If i were to buy this antminer, i could set it up at my office with no charge of electricity. But how much data would this pull out of the internet speed? i would like to mine litecoins, how long would it take to get back the investement cost? 6 months?
The internet data transfert is very few : don't worry about that.
But you can't mine LiteCoin with a AntMiner S9 : it is a specialized ASIC, only for Bitcoin.
To reply to your title question : 4 nVidia cards, but not for Bitcoin or LiteCoin, but one or several altcoins to choose as you want.