Each day you sign into Vegas World, you get some free Coins. These Coins are added to each Vegas World account the first time they log in each day.
The Daily Spin coins increase in value each day you log in consecutively, up to a maximum bonus of 7 days in a row. The reward grows for signing in every day, so if you miss a day, the bonus will drop but will start growing again if you keep signing in.
Up to five Daily Scratch Ticket Coins can also be awarded to you by your friends. Be sure to return the favor if they send you Tickets! Scratch Tickets are free for everyone, so it never hurts to send them.
If you run out of Coins and can't wait until tomorrow, you may have to spend some Gems to get more.
Spending Gems for More Coins
To purchase Coins you must select the Coin tab just under where your name and level are displayed (where your Coin total is displayed) There are two ways to purchase Coins. You can buy them straight from Vegas World or you can purchase Charms, which will give you more Coins for your Gems, but they mostly pay out while you play. Unless you've gone bust, buying Charms is always a better deal than buying Coins directly.
Coins cost Gems. You're guaranteed to collect the amount listed at the top. Example, if you select the 25 Gem option, you're sure to get 500,000 Coins. You may also get additional Coins up to the "extra bonus" amount, but those coins are not guaranteed.
Charms boost your winning wagers as you play. Standard Charms cost between 5 Gems and 500 Gems. The exact Charms you can buy rotate every few minutes (see the timer in the upper left?)
Charms purchased in the Charm Shop are known as "Standard" Charms. Unlike Party Favor Charms, these are just for you. Also unlike Party Favors, they can be recharged after they are used up. The value of each Charm is based on its Gem cost. So, for example, every Charm that costs 25 Gems is worth very close to every other Charm that costs 25 Gems. A Charm that costs 100 Gems is very close to 4x as valuable as one that costs 25 Gems.
Rare Charms - Each time you purchase a Standard Charm, you might get the Rare version. The rare versions have a different name, look a bit more fancy and they pay out a bit more Coins than the normal versions. The more you spend on a Charm, the higher the chance it'll be rare. 5 Gem Charms are seldom rare, while buying 100 and 500 Gems gets you far better odds for a rare.
Also Check out How Do Charms Work?