Hi Adrian
Four of us on this forum (don't know if there's others) bought our Chelyabinsk Russian meteorite from Mo's Meteorites (Germany) on e-bay. He's a trusted and reputable seller. Mine arrived complete with a nice presentation case and a laminated little certificate- I'm extremely happy with the presentation. Received within 7-10 days if I remember correctly.
Meteorite Men (Airlite site) didn't have any of those Russian meteorites at the time a couple of months back.
Make sure you do your math on the dollar conversions including the postage. Mine was selling for $105 but after conversions including postage came to around $135.
All the best with your purchase.
http://stores.ebay.com/mosmeteorites/