Pokemon GO requires the player to have an abundance of Pokeballs. They are often divided in categories depending on their usage and the experience level of the player.
The players start the game with regular Pokeballs and better form of these Pokeballs can be unlocking by reaching certain levels. Great Balls can be unlocked after reaching Level 12 while Ultra balls can be unlocked by reaching Level 20. Similarly Master Ball will require a certain level threshold before it can be unlocked, but it hasn’t been confirmed yet.
Once you unlock Great Balls, you will be able to get them after each level up that you do in the game. Similarly once you unlock Ultra Balls, they will be awarded by the game on each level up. You can refer to this article to learn more on what type of reward is given on each level up.
There is an easy way to level up. This method require the player to own a Lucky Egg. Since the egg doubles the amount of experience points earned in the game, it is essential if you want to level up fast. The Lucky Egg effect can last for half hour and any evolution and Pokemon captured during this effect can provide double the experience points.
Pokestops can often reward the player with Pokeballs but occasionally they can also get Master Ball, Ultra Ball and Great Ball. Since these are much rare type of Pokeballs, it is recommend to avoid using them on a standard Pokemon and instead save them for a potential legendary or rare Pokemon.
If you don’t have an Ultra Ball or a Master Ball, you can try to use Razz Berries in combination with a Great Ball for capturing the Pokemon.
Pokemon GO is available now for the iOS and Android.