Share purchased apps between iPods?

My place of employment is need of using and purchasing therapeutic listening apps from the app store for our patients. Our plan was to purchase the apps once and share the apps between multiple ipods at multiple locations.

-Is there a way to share purchased apps between 10 iPod touches?

-None of the Ipods have been purchased yet. Can we set them all up with the same apple ID and Password?

-We want to limit the amount of money we spend, so if we can purchase the app once and share between all 10 Ipods that would be ideal.

-Can more than one person be using the app at the same time another user needs it?

Thanks!