Let the hive mind of Engadget get that for you.
"As someone who doesn't reside in the USA, I was wondering what would be the best way to get internet for my computer in the US for a couple of weeks? If it were Europe I know I'd look for some prepaid data. Is there anything similar offered by American carriers? A MiFi or a data SIM that I can tether from would work, but I'm trying to maintain a tight budget. Help!"
a) The number 1366 would be derived from the average amount of solar radiation which falls on 1 meter squared at the earth's surface.
b) The holy grail pricing of $1 / watt is correct, but it relates to installation CAPACITY. Lets say you buy equipment to produce 1 kilowatt (1,000 watts) of power costing $1,000. Check your electric bill and compare this against what you pay per hour per kilowatt. I.e. for a customer paying 10 cents per kilowatt HOUR, would take 10,000 hours of operation to pay back the investment. Assume only 6 good hours of sunlight a day, that's about 5 years to pay back the investment.