You only save money...
on the devices. Any actual saving are computed by (cost of devices for the company) vs (the solutions the company has to buy to support BYOD, especially iOS in an AD environment plus the staff cost of supporting the devices). I am pretty sure the costs are, at best, break even unless you are a 10 person company.
Plus BYOD doesn't solve any real business problems unless the devices are on an approved list. I can tell you, I am NOT going to decide which phone I am going to buy based on whether or not my IT department will support it. I put BYOD on the list of ideas that never work because of the details, with a few exceptions. The only problem BYOD solves: users whining. Otherwise, IT can just give devices that already work with existing infrastructure, are secured and in full compliance.
