Playstation plus instant game collection

So, if i get a 1 year playstation plus subscription and download games like vanquish and arkgham city for free how long can i have them

do i own them or are they gone like in steam where some games are available for the weekend?

If it's a free game it usually expires when your Plus subscription expires. If you re-sign up for Plus you get access to those games again. If it falls into this category it will come up with a message saying so when you "purchase" the game.

If it's a discounted game it's usually yours whether you have Plus or not.

Thankks fot the info guys