Re: buying mistake
As for the return, that honestly is going to depend on the return policy of the store you purchased it from. My guess is they will not refund your money or give you credit for the difference.
For another 90 bucks or so you could upgrade your RAM, and save the othe 210 bucks for an extrenal hard drive of 1 TB or more. IMO the 800 dollar one is a better deal, while less ram and less hard disk space, for the difference of 300 dollars you could easily upgrade your rame and get an external disk drive for less than 300 bucks.