lets say I get 6 x 290/390 on good price thats 150-60 mh/s on current rate(249$) and difficulty my profit will be 575$ without the electricity bill which I'm not paying

Ok but you cant buy those new so they'd have to be used, also, how do you expect to get a good deal in Italy? You'd be almost limited to the used market in Italy as most people wont ship to foreign countries.
I dont think youll be able to get R9 290/390 for less than $399 usd. its not worth it at all man.
You're going to need 2 power supplies if you want to run 6 290/390 on the same board so what about all the upfront cost for that?