Earlier this year, Microsoft announced a new game service. For a monthly cost of $9.99 USD a month, you will be able to download and play any game made available through the service on your Xbox One.
So for the cost of Netflix you will have full access to at least a hundred Xbox 360 and Xbox One games. There will also be a discount if you chose to buy any game currently on the service, as like with Netflix there will be shifts in the content. The line up will change over time, so you may need to still purchase a game you enjoy if you want to keep it.