Microsoft's Xbox Game Pass is a pretty good subscription service, having over 200 titles for your Xbox available to play whenever you want. When you throw in first party titles available on day 1 (like Crackdown 3 and Forza Horizon 4), and the ability to get cross play on PC for these same titles, it is an even more attractive service.
Looks like Microsoft is wanting folks to give it a whirl, as they are running a really good deal right now for those that are not subscribers. You can get two months for $2 by purchasing one month for $2 and getting the second month free. If you are worried about getting charged for the $9.99 monthly fee once the two promo months are up, you can easily go into your Microsoft account online under Services and Subscriptions and turn off recurring billing for the Xbox Game Pass.