The model I posted? Let me know where you get the best deal for the machine and refills..
There is a non-Nespresso brand that makes (almost) compatible capsules sold abroad and on Amazon. One of their varieties is around half the price of the Nespresso ones (search "coffee capsules"). There are also two or three manufacturers of "fill your own" -- also sold on Amazon.
Otherwise, I have not figured out any way to buy the Nespresso capsules for less that the price sold on the Nespresso website. They don't seem to be sold anywhere else -- lots of places sell the machines, but not the capsules. Their patent expires soon -- so one of these days we'll see other manufacturers.