[quote name='DarkZion']Well if you're like me, you're currently unemployed. In which paying taxes on $600 is more than I technically make in a year.[/QUOTE]
That makes no sense at all...
You would add the value of the prizes (as indicated on the 1099 misc you get from Bing early the next year) to any other income you may have had in 2010, and then subtract the standard deduction. If you haven't made more than $5,700 total for the year (including the value of the Bing prizes), you won't have to pay any income taxes.
The point is that you would end up paying the taxes on ALL of the prizes ordered with that account, and not just the prize that put you over that limit. So, if the Bing prizes were your only taxable income (assuming you made exactly $5,700 from other employment), you would end up paying 10% of the value of the prizes, so roughly $60, or more depending on how many additional prizes you order past that W-9 mark. Considering you can easily sell one of the major prizes for at least double that, you would still come out ahead in the long run. Obviously, if you were otherwise wealthy, you could pay as much as 35% of the value of the prizes (i.e. you had more than $400,000 of taxable income), but in that case I doubt the extra $210 in taxes would be of any real concern anyway.
Basically, how the W-9 affects you will depend entirely on your tax situation. For some people it won't cost them a penny, but for others it could cost as much as $210, to get those $600 worth of prizes.
Also, keep in mind that the tax year is based on the calendar year, so you can order prizes with the remaining tickets on Jan 1st 2011. Just be sure to keep the account active or the tickets will get zero'd after 6 months. Simply logging in is not considered active, you will need to do something that affects the tickets, like playing a game, or donating 1 ticket to charity.