You should not preload applications.
Applications purchases are tied to an iTunes id. So when it comes time to upgrade the person will need to know the iTunes id/password.
Instead you recommend apps to people. Each user should create their own iTunes id and purchase apps using that.
If you deploy a MDM solution like MobileIron, etc, you can use the volume purchase program (VPP) and assign tokens to users. This way they don't have to charge the app purchase to their credit card.
I would highly recommend you invest in an MDM solution as it will help you in the long run.
Hope this helps,