Bitcoin ASIC devices are still being developed so there's quite a bit of prices ranging from $26 or so for 333MH/s on Ebay to Cointerra with their 2 TH/s for $14,000.00 so which one should you get?
WARNING: if you care to look at how I come to the numbers I have on estimated difficulty and price read on, if not, skip to the... ---
Well if you take a look at the electricity efficiency, the cost of the device per GH, and also considering the times that these devices will arrive to you, it may help you to see the bigger picture. Which device is likely to be the most profitable after a years time from today?
Estimations are roughly based on the following difficulty estimates (these estimates are based according to devices pre-sales and other factors including TH to Difficulty conversion rates):https://bitcointalk.org/index.php?topic=283820.0
September Average: 125,000,000
October Average: 700,000,000
November Average: 840,000,000
December Average: 1,260,000,000
January Average: 1,372,000,000
After this I added the last growth between December and January, 112,000,000 per month
While these numbers for difficulty are likely to be fairly accurate, I would give them a +/- 300,000,000 from Oct-March on and +/- 500,000,000 from April - Sept.
Now for Price estimates:
This estimation on bitcoin value is harder to gauge because it's largely based on acceptance/demand. The more this currency is accepted the more likely the demand will increase. Also as the difficulty to obtain more bitcoins increases the rate in which the value increases (yes I said increases twice on purpose
So here's the pricing estimates based on the difficulty estimates and historical behavior to situations. Difficulty estimates although in the long run will likely increase the value of the bitcoin.
When mining difficulty grows in difficulty at first you may notice a price drop, because many of those who have invested in mining machines want to sell some/all of their bitcoin gains to recoup the costs of the machine they invested in which increases supply (i.e. that is what I believe happened from sept 2 - today sept 10 http://bitcoincharts.com/charts/mtgoxUSD#rg60ztgSzm1g10zm2g25zv
Bitcoin Value estimations:
Too many factors are included to give an accurate gauge with a reasonable +/-. But you can decide for yourself how accurate you believe these numbers to be, and add or subtract accordingly.
Keep in mind these are all estimations, and are therefor likely to be 100% inaccurate for exactness in accuracy.
Ok now finally the fun part the results:
Depending on how much you can afford, or want to, will determine which rout you may want to go:
Cost GH Rate Month available 3 Months Revenue Revenue in 1 year ROI (100% = break even)
USB Miner $28 .333 Now (Sept) $3.86 $9.23 33%
Mining W/ Hosting $249 25 December $155 $494 199%
BFL $4,680 600 February $3,970 $9,496 203%
KNCMiner $4,999 400 November $3,888 $8,856 177%
Cointerra $13,999 2,000 December $12,400 $39,570 283%
Also it may be good to note, that if Bitcoins continues to become increasingly valuable, in 2017 I expect a large jump in price as the populace realizes that coins are going to be even more difficult to find as they did in 2013 (but maybe this time with a little less volatility due to past experience in the change).
I personally would recommend cointerra if you can afford it because of the ROI and its energy efficiency. Otherwise I'd consider looking at the link below for the Mining w/ hosting since you can get basically get the quantity you desire.
$28Mining w/ hosting