BTC : $103 / 0.02 = 5150....But that is more expensive that your PCs which you are also using for other purposes.
You make an important point here. MemoryCoin is a CPU coin and is designed to be most cost-effective by mining it on equipment that you already own . . . where the hardware is already a sunk cost. I'd be surprised if (in the long-term) it is possible to profitably rent or buy equipment to mine with. The price should thus be at about the cost of electricity required to mine, speculation aside. That's not to say the price (and difficulty) can't be high, just that it isn't at the moment.
Hashes per watt of different equipment is an important metric.
On a very low end, but energy efficient media pc, i'm seeing
1 hash per second - 20 watts