As shown in the pictures, the total power usage in 24h is 0,391kw/h, the price on a 0,17€kw/h is 0,06647€, for the moment is profitable but I dont think I will get back the cost of the block erupter.

https://www.dropbox.com/s/6nnqs2jhmh0i1bi/2013-09-07%2013.49.05.jpg

https://www.dropbox.com/s/efxgxwrxqwlyzkt/2013-09-07%2013.47.46.jpg