Your understanding is all correct.
While Events are printed on cards in a landscape shape; the event itself is not a physical thing like a card, but rather an task or action that you get to perform. Each time you buy an event you use up 1 of your buys (and however much money it cost). So if you have enough buys an money, you can buy an event repeatedly.*
From the Empires Rulebook:
Events are not Kingdom cards. In a player’s Buy phase, when a player can buy a card, they can buy
an Event instead. Buying an Event means paying the cost indicated on the Event and then doing the
effect of the Event. The Event just stays on the table, the player does not take it; there is no way for
players to gain one or end up with one in their decks. Buying an Event uses up a Buy; normally a
player can either buy a card, or buy an Event. A player with two Buys, such as after playing Villa,
could buy two cards, or buy two Events, or buy a card and an Event (in either order). The same Event
can be bought multiple times in a turn if the player has the Buys and available to do it.
*Note that certain events from the Adventures expansion specify "once per turn" or even "once per game". These are an exception to the usual rule of being able to buy one repeatedly.
