Find out if your state has an assistive technology lending program also if he has State insurance and he is in school you can ask the speech therapist to solicit the state for a device.

I'm looking at this app called LetMeTalk, it seems to have some of the things we're looking for, but it's hard to tell without playing with it myself. Have you ever tried that one?

Dynavox has a program you can download to a tablet. https://www.tobiidynavox.com/en-US/software/win...
It won't work on a Kindle, you would need an Ipad or they have a windows version too that you could use on a tablet.

My state Mass will give us an electronic tablet with programs on it. My grandson is on Mass Health. We have to go to a speech and language pathologist first and if they think he could benefit from it we should get one. I just found this out today.
I also was thinking about grants from Autism organizations and I found and organization called Danny's wish and I think they will give you up to $5,000 for necessities for your child. they will only pay a vendor you don't get any cash yourself. So if you find a device that you like let them know about it and maybe they could help you out. I think they give they money out in the spring.

http://www.friendshipcircle.org/blog/2011/03/09...