The AnyConnect license comes in two flavours. A very grand mistake that most have made is around the cost.
Essentials @ circa. £400 for 5000 client licenses based on the hardware capability
SSL/IPSEC Client license per active device. This provides both full and split tunneling access to the central point of presence.
Premium @ circa. £180 each for client licenses based on the hardware capability
As above. However, this also includes the secure webtop (similar to a Citrix CAG), secure file access, etc.
The key to remeber, is that you cannot run esentials and premium on the same box. If you license in one model then that is what you must maintain.