You make me laugh. 300 Khs is nothing for $300. for $450 you can buy a graphics card that can give you 1.2Mhs.
Also for the newest scrypt miners coming out, it is still twice as profitable buying a terraminer and mining sha256 coins from coinwars.
No one really has $7500 for a scrypt miner anyways when the only thing you really save on is electrical costs.