Yes, TestComplete can be used for testing QT GUI applications. TestComplete supports testing desktop, web, and mobile applications, and has built-in support for various programming languages and frameworks, including QT.
To run automated tests on an i.MX6 board, you would need to install TestComplete on a computer that can communicate with the board over a network connection. You would also need to ensure that the TestComplete agent is installed on the board.
Regarding the cost of a TestComplete license, it depends on the edition and the number of users. The pricing information can be found on the SmartBear website, and you can contact their sales team for a quote specific to your needs.