If it's like the one described on this page --
http://www.victor-victrola.com/XVIII.htm-- this was a high end model in its day, and desirable among collectors today, especially if the cabinet is in very good condition, with the original finish intact, and all parts original and working .
Before the global economy tanked, one in excellent condition might have sold in the $2,000-3,000+ range, but now, it's hard to say. I know of one that sold recently for about $1,200.00 that was in what I'd call good condition--a few scratches to the finish, but restorable; some wear on the gold plating; and the (spring wound) motor working, but in need of a complete overhaul.
If selling it, an auction might be your best bet. To save yourself the hassles involved with shipping, limit it to local pick-up only.
I should add that there is a VV-XVIII listed for sale on this page --
http://www.intertique.com/VictEighteen.html The cabinet is what I would call average-good condition, though the unique V-pattern wood grain on the doors is clearly visible. The asking price is in the upper range of what I've seen these sell for over the years. It's been for sale for awhile now. Again, the economy has had a major impact on overall selling prices of all antiques, and Victrolas are no exception.
Hope this helps,
Joe