Hard to give you an exact answer, because I dont know, and probably shoudnt know, where in Europe you are based. As far as i know there should be some local sites like craigslist.
If youre a little bit crazy, go to an auction, where the "stolen equipment" from fellow growers is beeing sold. Theres a shop selling cuttings in CH, who uses a huge pile of 600w ballasts, bought for 15 CHF a piece....
