how much BTC can I get IF I buy BFL 50 GH/s Bitcoin Miner - $2,499
BitForce 50 GH/s SC ?
Depends on a couple factors:
1. When you actually get the unit.
2. How much the difficulty increase between now and then.
Let's run some numbers!
If you somehow got a 50GH unit right now, you would be making about $364 per day.
I think Butterfly Labs is predicting at a two month wait, by which time the network hash rate will probably rise to something like 300TH/s, making the difficulty around 42 million. Still, you'd be making $77 a day (if the USD/BTC exchange rate holds).
My guess is that it's going to be *at least* 4 months before you see that unit. It's hard to predict how fast the network will be by then.
If the network gets to 500TH/s, the difficulty will be around 70 million and you'll get $47/day.
1PH/s (1000TH/s) will yield a difficulty of 140 mil and 50GH/s will net you around $23/day.
1.5PH/s and you'll be getting $16/day.
And all of this is assuming that the exchange rate stays around US$130/BTC. If it drops back to $30 where it was before the recent madness, those numbers become:
500TH/s: $10.80/day
1PH/s: $5.40/day
1.5PH/s: $3.60/day
Even if the exchange rate stays high, and you get your unit before the difficulty climbs too high, you won't pay it off instantly. The difficulty is going to keep climbing while you're paying off your unit. It might start at 42 million, but it might be 50 or 60 million before you've paid off your unit.