What price per GH/s is worth it to purchase right now?
With this calculator http://www.alloscomp.com/bitcoin/calculator using a BTC price of 75 USD and current difficulty one GH/s will mine $53 in a month. How should one project out after that to account for the rise in difficulty? Just half the dollar amount to account for a doubling of diff every month?
$50 month 1, $25 month 2, $12 month 3, $6 month 4, $3 month 5, $1 month 6 ?
Is 1 GH/s only worth about 100 USD right now, or is my admittedly very crude estimation too pessimistic?
With this calculator http://www.alloscomp.com/bitcoin/calculator using a BTC price of 75 USD and current difficulty one GH/s will mine $53 in a month. How should one project out after that to account for the rise in difficulty? Just half the dollar amount to account for a doubling of diff every month?
$50 month 1, $25 month 2, $12 month 3, $6 month 4, $3 month 5, $1 month 6 ?
Is 1 GH/s only worth about 100 USD right now, or is my admittedly very crude estimation too pessimistic?
I think it comes down to how long will it take you to pay off the rig, then you calculate electricity vs coin value. A safe number is probably how much you can get in 30 days, so $53. Since difficulty changes 2-3 times a month, you should be able to get it paid for in under 2 months. Then calculate how much electricity costs and calculate at what difficulty level and estimate price would you need to shut down the device. If you have free electricity, you are lucky and should just get the unit paid off and run it til it dies.
My rig is paid off and if I had to pay for electricity, it would probably be off (or sell the parts and purchase coins). I think that is the other piece of the puzzle. Once you can't run it-- being able to sell the components is a great thing. Probably can't sell an asic which cost more to run than what it mines but you can with each computer part. (then again, the USB Block Erupters are selling even through it doesn't make much sense. When I saw them sell for $400 each, I couldn't believe my eyes) I recently saw a BFL 60GH/s sell for 153 BTC. How crazy is that? Not sure where I'm going with this...
Short answer = whatever 1GH/s can get you in 30 days.