I told you it wasn't cheap. If you want long range wireless [bluetooth] (which is what you need if you want to go over 6') then you're going to pay. At least for now. Of course, you COULD put the receiver closer to where you'll sit and then have the keyboard and mouse within the 6' range of the old technology wireless. Get an USB extension cable and you might be able to stretch it even more. Of course, that might not be as pretty as you want, but if you're too cheap to pay, then that's what you'll need to do.
Also, I won't buy any techology off of ebay that's not brand new, or has a warranty that can be transferred to the new owner and still have a long period left. This goes for ANYTHING with electronic or moving parts from cases to mice to memory to drives of all kinds. If the manufacturer won't cover something that's changed owners, then the warranty is useless and I wouldn't recommend ANYONE get the item.
BTW, that's just the prices listed on Logitech's site... Do some searching, I'm sure you can get it from a legit source for less. Actually a FAST search on newegg (use the search function) shows that they have it for $145 (the Cordless Desktop MX for Bluetooth). The diNovo is listing for $189 there... Check with other resellers, you might be able to get either for even less.