You can purchase additional ATMEGA328P-PU controllers, USB programming cables, etc., on the Arduino Accessories page.
The official Arduino Starter Kit [English] (Original - Made in Italy) includes a 170-page basic Arduino learning textbook in English, an official Arduino Uno Rev3 board, and accompanying components that allow you to start exploring Arduino according to the curriculum compiled by Arduino.cc, the organization that invented Arduino. Through basic lessons and 15 interesting projects, you will be introduced to the world of Arduino in a vivid, intuitive way and easily master Arduino for subsequent exciting projects.
The official Arduino Starter Kit [English] (Original - Made in Italy) includes:
1 x Project book (170 pages), 1 x Arduino Uno, 1 x USB cable, 1 x 400-point breadboard, 70 x Solid-core jumper wires, 1 x Easy-to-assemble wooden base, 1 x 9v battery, 1 x Stranded jumper wire (black), 1 x Stranded jumper wire (red), 6 x Photoresistor, 3 x 10kOhms potentiometer, 10 x Pushbutton, 1 x Temperature sensor [TMP36], 1 x Tilt sensor, 1 x Alphanumeric LCD (16x2 characters), 1 x Bright white LED, 1 x RGB LED, 8 x Red LED, 8 x Green LED, 8 x Yellow LED, 3 x Blue LED, 1 x Small DC motor 6/9V, 1 x Small servo motor, 1 x Piezo capsule [PKM22EPP-40], 1 x H-bridge motor driver [L293D], 1 x Optocoupler [4N35], 2 x Mosfet transistors [IRF520], 3 x 100uF capacitors, 5 x Diodes [1N4007], 3 x Transparent gels (red, green, blue), 1 x Male pin strip (40x1), 20 x 220 Ohms resistors, 5 x 560 Ohms resistors, 5 x 1 kOhms resistors, 5 x 4.7 kOhms resistors, 20 x 10 kOhms resistors, 5 x 1 MOhm resistors, 5 x 10 MOhm resistors