Make sure you know exactly what endpoints will be utilized for the solution. The only difference in price is between Standard Endpoints (Windows workstations, Linux, Cisco, etc...) and Servers (Microsoft Server 2008, 2012, etc...). Make sure you know if you are going to use this on just servers and workstations or if you will also include network devices, printers, IDRACs/ILOs, VMware ESXi and others.

The pricing for Lieberman is cheaper than the others that are in the market. The licensing is complicated but a lot of the privileged accounts are. 

Have a good roadmap defined so there are enough licenses to complete deployment and handle future growth. We had to pause our deployments until we purchased more licenses.

Do a full PoC in production. The AD discovery data alone usually shows people the true scope of their password issues. It will also reveal how many licenses will be needed.

Workstations, which are often an afterthought, are an attractive attack surface. I would include them in the PoC as well. The licensing for workstations is pennies on the dollar compared to servers.