The S&W .44 magnums from the era you describe are the most sought after versions. Later versions have a locking mechanism that is not a popular feature among shooters. So the guns from that time period are generally as expensive as brand new .44 magnums.
The 29-4 might be the best choice (according to the shooters here - most don't like the locks). If you're interested there are also stainless versions of the guns which are given the 629 model name. There are also various dash versions of those guns. Many prefer the blued guns for their looks. Some prefer the stainless models because they resist rust better. You shouldn't have a lot of trouble finding one. S&W built a lot of them.
Here's an example of what a current production 29 costs. Prices are between $889.99 - $1,119.99.
Smith & Wesson Model 29 Revolver | Sportsman's Warehouse
Here's a gun from the time you describe listed on Gunbroker, which is basically eBay for guns. It's not a blued gun. It's nickel plated. It's a 29-2 in very good condition. It has a 4" barrel and their asking price is just over $665. Blued models generally are more expensive than nickel plated models I believe.
http://www.gunbroker.com/item/637030245