Hi,
Ok you do not need the paid version you just can only have 100 iPad's then after that you have to pay. I've got this working at nearly 20 schools now. What you need to do is have iOS 9.0 or above. Then use the device assigned way to push apps. You don't need an itunes account at all linked to the iPad's or signed into the iPad's it's all done via serial numbers and owners.
If you have any questions about how to get this done just PM me
Thanks,
Matt