You should check out the tools mentioned in the older threads. Most if not all of the tools are still relevant. Look at all the links to tools in the navbar as well.
Cost-effectiveness and easy-to-use must be determined by you and your organization. What is low-cost and easy-to-use for someone here might not be understandable to you and it might just put your company on the US Gov't Bail-out list.
Most popular automation tools I think will do basic GUI application testing on that app. You'll have to try them out to see if there are inherent incompatibilities with your particular product.
As for cost effectiveness.. It's really hard to say. Most of professional tools I've seen don't sell on store shelves and you need to talk to a sales person to get pricing. A lot of haggling I can't even comprehend goes on (done by our purchasing manager) and we get a price. Some tools are generally cheaper due to having less features, but then you can sometimes get a good deal.
It's like buying a car, Infinity are generally cheaper than Lexus.. But you might find a good deal on a Lexus and prefer it much better than the Infinity.
If there is a testing conference coming up, I'd suggest attending and talking to various sales reps and getting them to demo it for you. That'll give you a sense of which tools meets your requirements very quickly, then you can start calling around for the price.
Thanks guys.. I finally zeroed in on White Framework, which is an abstraction of the Microsoft UI Automation Library. Its very easy to use with any .NET language, although its not for the testers who prefer staying away from programming.
May you have a look on Ranorex, which supports automation for WPF applications. It allows to do test automation by programmers using .NET languages like C# too. Additionally, Ranorex provides a repository file to separate identification information from test automation code which is commonly used to increase maintenance of test automation modules.