Currently, there are 54 total operators available in Rainbow Six Siege, but not all of them are available at the same time. There are rotations where characters will become free to play, with about 8 of them being free to play at any time. The others are locked behind a paywall.
To pay for the operators that you want, you’re going to need some of Rainbow Six Siege’s in-game currency. There are two types of currency in the game, Renown and R6 credits. Renown is earned by completing matches and levelling up.
The better you do during your matches, the more renown you will earn. If you lose a match, you will get around 100 base renown by default. However, depending on your performance during the match, you are granted more on top of that. If you win, then your base earning is increased to 200 with the additional bonuses for good performance.
R6 credits are another currency which is purchasable with real money. They require much smaller amounts in order to buy operators, skins and bundles.
All the Operators are priced differently in Rainbow Six Siege. Older operators are available for 1000 renown and are not purchasable with R6 credits. More recent additions to the roster of Rainbow Six Siege are available for 15,000 to 25,000 Renown and up to 600 R6 Credits, which equates to around 5.00 Dollars (USD).
Bundles are also available that have multiple operators inside. Depending on which one is available, some bundles will also give skins for both your operators and weapons too. However, do keep in mind that these bundles are usually only available for purchase with R6 credits.