Appcessible.org have a great post up at the moment that lists 15 Free Apps for iPhones and iPads specifically for individuals with an autistic spectrum condition. You can run through the list on Appcessible, and click through and download them directly from the site.
Appcessible is all about apps that are designed to help users with additional needs. "Whether it’s an app to find the nearest disability friendly toilet or offer support around challenging behaviour, we want to list it."
The apps on this particular list are for Apple products, and you can access them directly from their page. There's no charge for using Appcessible and while some of the apps are chargeable, this list - as it says on the tin - is free.
There are some amazing looking apps here for children on the Spectrum, including one that helps children deal with emotions via gorgeous flash cards and interactive games, one that doesn't require any language or reading, and even options for totally non-verbal children and adults.
Even if this isn't something you yourself need, you may know someone who could benefit from them, and support Appcessible at the same time.