Apple currently does not allow developers to offer multi-user licenses on the App Store. If your company or organization is part of Apple's Volume Purchase Program for Business or Education, it's possible to purchase licenses under a single account and distribute to users as needed.

If your company or organization isn't part of Apple's Volume Purchase Program, each unique device used by a different user needs to purchase the app using separate Apple ID's.

Please note that for business/commercial use, any time an app is going to be used on multiple devices with multiple users, each device needs to have a separately purchased copy installed. This is covered in section 'ii' under "App Store Product usage Rules" at the following link. (I've also linked to the EULA)
http://www.apple.com/legal/internet-services/itunes/us/terms.html
http://www.apple.com/legal/internet-services/itunes/appstore/dev/stdeula/