Well the last 03a3 that came my way was $350 for a Smith Corona in excellent excellent shape. Now they may be a little more than that depending on condition and where you live. I wouldn't pay more than 500 at the top end. If it is less than 300 make sure it is not a National Ordnance POS 03a3.
Since you havent mentioned which model 03 that is about the best I can do. Check out Fjestad's Blue Book GV
Last gunshow in South Carolina, one guy had several - prices started at $400 for an O3-A3, $500 for a "USMC" 03-A3, some 03's - didn't get the prices..
Sorry I had to edit this because the web site is down right now. But these guys do great work in refinishing old military arms and selling them. They got some good stuff. My next Garand is coming from there.
[This message has been edited by MP Freeman (edited August 20, 2000).]
Once saw a Pederson Device for sale at a gunshow in Richmond, Virginia, complete with holster and cleaning kit. Price = $15,000. It was not one of the rusted, recovered versions from when the Army, after WW1, destroyed them by burning.