There is also sewitsforsale, a yahoo group that you can join and then do a search for listings for a specific item. A quick check didn't find a Virtuosa 160, but has had listings for a 163 ($1,000 included shipping in US lower 48) and a 153 that was $700 plus shipping, est. to be about $60.
There is a current listing for a 153QE that started at $1,500 and has been reduced to $1,200 but, frankly, that still seems high to me. That model was my original Bernina, I still have it and love it, but wouldn't want to pay that much for a used machine. Fairly sure I could get one for less than that @ the local Bernina machine shop, and I would know the dealer.