What? The Trainer is evolving! Welcome to level two.
A level two trainer will now realize that there is more to Pokémon than their starter, and will commence training full teams of six. Once again, these Pokémon will most likely be selected by how cool or cute the trainer judges them to be. A level two trainer will generally train their Pokémon with a degree of equality, but some will keep their starters as their star player, keeping them several levels higher than their other Pokémon. The value of rare candies will, appropriately, be surpassed by that of the Master Ball at this point.
In the Pokémon world, their exists a monumental invention called the Pokéball. The Pokéball replaced the cage before anyone can remember, and boasts a safe and easy way to capture wild Pokémon. Pokéballs are available for purchase at Pokémarts. As of Pokémon Black and White, these markets are found inside Pokémon Centers, not as individual buildings. However, when a trainer first stumbles into one of these stores, they will realize that their merchandise is rather limited, often only Pokéballs and Potions. No need to worry, the trainer is simply not qualified to buy anything else. In order to gain this qualification, the trainer must first attain Gym Badges. Once the trainer has all eight gym badges, they can purchase a huge variety of items. Not only can they buy new items such as Repels (which keep wild Pokémon away so long as their weaker than your party's leader) and status restoratives (which heal off paralysis, burns, poison, freezes, or sleep), but they can also buy improved versions of past items, such as Hyper Potions, which restore two hundred HP as opposed to the standard twenty. Their are dozens of varieties of Pokéballs, most of which cannot be purchased by normal means. The ones that can are Pokéballs, Great Balls, and Ultra Balls.
All kinds of Balls operate off of a statistic called the Catch Rate. The weaker the Pokémon, the higher the Catch Rate. The higher the Catch Rate, the easier the capture. Pokéballs factor into this as well. A Pokéball has a basic Catch Rate of 1.0, while a Great Ball's Catch Rate is fifty percent higher at 1.5. An Ultra Ball's Catch Rate is twice as high as a Pokéball at 2.0. Other Pokéballs Catch Rates rely on the target's stats. For example, a Heavy Ball has a higher catch depending on the target's weight. Other Pokéballs' Catch Rates depend on when the Ball is used in battle. A Quick Ball has a Catch Rate of 4.0 if thrown on the first turn of battle. Though this is substantial, its user foregoes the advantage of weakening the Pokémon with attacks and status conditions. Then there's the prestigious Master Ball, the ultimate device. The Master Ball ignores catch rates completely and catches its target without fail. Keep in mind that the trainer only gets one Master Ball per playthrough, so it must be used wisely. Also bear in mind that a trainer can only catch wild Pokémon, and it is impossible to capture another trainer's companion (with an exception in Pokémon Colosseum and Pokémon XD: Gale of Darkness). Until Pokémon X and Y, the trainer's Pokémon did not gain experience points from capturing Pokémon.