There is a free trial available for up to 700 words of text-to-speech with no credit card required.

Narration Box offers three paid packages with different word limits and pricing, with the lowest cost package starting at $9.99 per month.

There seems to be no public information about any refund options. As its paritally free tool, it is likely that once you make a payment, there is no option to refund it.

Narration Box provides customer support via email and a chatbot available on their website.

Narration Box has integrations with Zapier, Google Sheets, Spotify, Apple and Google Podcast. The public API for developers has currently "coming soon" status.

Some of the main features of Narration Box include various voice and accent options, the ability to adjust speech speed and pitch, and the option to download the audio file in multiple formats.