Well, Primedice is the best site I have ever know, if you play there, so many wins can you get even more in almost every month Primedice hold a contest that could make members get many bitcoin, but if you do not want to try Primedice, maybe you should look for better than that, and you might try playing in SatoshiGames.io 
Not every month. They are running contests weekly and one of the best feature i love is the forum reward for contribution. It is far better than faucet. Moreover, there are daily trivia competitions, chat games, rains and more.
I couldn't remember if it was on Primedice or Bitsler but back then I always receive some free sats from them.
I couldn't remember since I tried so many gambling sites.
But for me I would definitely stick to stake since it have so many games and I like almost every game in it,
And the way that they manage it is the best for their gamblers ,
They aren't just taking profit but also giving us back by having challenges and give aways.