Interesting question was asked during the user group meetup today and it was about CALs used with SQL Server 2016 Standard Edition. When we purchase CALs for Standard Edition, should we consider only about concurrent connections or all users we expect to connect with it?
As per the reading I did, it is NOT for concurrent users. It is for all users or devices connect with SQL Server. Assume that you have a web application that consumes data from SQL Server using a single user account. And web application is used by 100 users for doing various business, of course, accessing the database via the application. Then, if the SQL Server is based on CALs, you need to purchase 100 CALs, not 1 CAL.
Remember, CAL can be connected to any SQL Server instance. You do not need two CALs for connecting to two SQL Servers.
Microsoft licensing model was bit complex but now it clearer than it was. This PDF gives you enough information to understand the licensing models.
If I am not mistaken, there is no Microsoft web page to get pricing on SQL Server, you need to talk to your local vendor on it.