RUST Coinflip is a casino game in which you can win RUST skins. It's simple - you and other player bet skin/s that are the same value and you both get a 50% of chance to win. Coin flip decides the winner. If you win, you will get your deposited skins back and skins deposited by the player you've won against. You can create a coinflip and choose the coin side or join an already existing coinflip.
On some sites, you can "ask" a bot to join your coinflip. It's an extremly useful feature as with larger coinflips you can wait even hours in some cases for somebody to join. And if you have a choice of asking a bot to join your coinflip you can simply do that, if you're tired of waiting.
Some RUST Coinflip Sites will offer free bonuses. Some of them will be free coins for new users, others deposit bonuses. Make sure to check if the site has a referral code that you can enter to claim the bonus.