Gambling relates to a risk of financial loss
Gambling must have the potential loss of consideration. This does not necessarily mean just money because a person can gamble with a watch, car, or something of value . In addition to the consideration requirement, gambling must be primarily motivated by profit or gain. Freerolls in my opinion would not be considered gambling because although there is a financial prize, there is no consideration for loss present as a requirement for playing the game.
A door prize to an event is not considered gambling because gain is not viewed as the primary motivation for attendance. This is also true of a poker fundraising tourney. To simply play monopoly is not gambling as the loss of time is not considered as being a form of consideration. Investment is not gambling because it is considered as a means to raise money for the purpose of doing business.
It also should be considered that a freeroll is not a true form of poker and limits poker learning because the loss of consideration is not incorporated into the decision making process. The lack of consideration explains the abundance of "all ins", loose "calls" of "all ins", and the willingness to play
hands that people would otherwise fold.