World of Warships (free game with limited-time cash value bonuses for signing up)
New players joining using this referral link will, after a bit of playing, receive two free premium ships. One game (maybe 10 minutes in length) earns you the soviet ship Diana (currently on sale for $10) and if you work your way up a few tiers (maybe an hour of play) you'll earn the USS Texas (limited availability, previously around $25.)
There are also other small bonuses that won't mean much if you don't play (flags, in-game credits, and port slots), but come to maybe $10 value.
No, none of this can be sold. But if you've been hearing about this game, or like the idea of a naval fleet battle, it's a nice bonus for trying it now.
The offer is open to new players, plus any players who haven't logged in during the last three months.
And yes, if you use the link above I get a small referral bonus, though no free ships for me. And another note - this is not one of the "pay to win" games. You can easily play the entire game without spending a nickel. These premium ships will get you off to a good start, but sorry, skill will tell.