You just need a US voltage power supply... if youve got an old A500/600/1200 power supply it will work. I use my old A500 power supply, which is actually better than the original A1200 power supply. You can find these on ebay or ask people here... should be cheap. Just get the Amiga from there with no power supply. Also recommend no hard drive, as a 4gig drive on ebay will cost you under 10 bucks. Just get the computer, the OS 3.1 install floppies (if you dont have these already) and optionally a RAM expander (if you plan to get an accelerator, skip this... if not, its reccomended).
A US power supply will work on a European Amiga. The PSUs all convert to the same voltage.