Can you please advise if this is a free download?
It's impossible to say what is the actual price of the application since there is no information about it. I've checked the official website and it appears that TTS Online was discontinued. There is no trace about it or any form of troubleshooting. I've visited the developer's website to search for TTS Online and no results were found.
You can use other apps as an alternative to TTS Online. Browse the following page and drag the slider on the Relevance side: http://software.informer.com/search/text+to+speech