just like anything else, it depends on the demand in your area. I found my contender for $325. In San Antonio, just a couple hours east, you'll see them going for closer to $400. Encores seem to go for about $50 more than a contender.
Once you get your first set-up, you can find most of the common caliber barrels here or on E-bay for under $150-$175 if you wait for a good buy.