NHL Salary Cap
In 2005, for the first time in league history, the NHL Collective Bargaining Agreement instituted a salary cap. The fiasco and lockout in 2012 led to further restrictions in terms of cap limits, buy-out opportunities, amnesty clauses, and how a player's contract amount applies towards a team's minimum or maximum spending limit.
This site is NOT a great resource for salary cap information and figures. For that, look into the sites below.