uh oh, more fuzzy math.
The $100 rebate you reference is only $50 for the 870, $100 for the 875DC
and the last link you have there is for a 980.
EDIT: At the bottom of the almost illegible rebate form at computers4sure, it says that if the purchase is from Staples or Costco, you need to submit the rebate through them. Curiously, the rebate link at staples doesn't work. D'OH!
I can't believe Epson's fuzzy spelling: 'eligable'