I think Amazon sells a lot of things international don't they?
I buy most of my hardware at Newegg or Amazon. As I understand it most everything computer related is cheaper in the US but I'm sure that's not always true. I have no idea where to get stuff sent to Greece. I'm sure you could find things on eBay but it would be expensive I bet.
I bought both of the graphics cards on Hardforum.com (they have a really well set up trading forum), the Superclock Ed. was brand new in box right after AMD put out the 290s. The other card I bought used but it showed up mint and came with both of the backplates.
I'm learning how to modify cheap old steel cases right now, so there's a lot of really rough cuts around the drive cages in that picture, I pulled a lot of that metal out with wire cutters and then repainted it... The Dremel I have is crap. I'm replacing the low profile 140mm heatsink with an NH-D14 which will probably still look really weird, but I found a good 4770k and I want to see how far I can push it. I even have a vice I pulled out of my dad's workshop to delid the thing with if I can find the balls.