Pay $20 and you get the number permanently. I've set up my kids' soccer club and my son's Cub Scout Pack with voicemail-only numbers. Callers leave a message and a recording and a transcription is forwarded to the appropriate person via email.

I've also read using Google Voice is highly recommended for things that require a voice or text number since it's very difficult to get hold of someone at Google that can be socially engineered. Much easier to scream at somebody at Verizon, etc.