The PIC16C84 was introduced in 1993 by Microchip and the first PIC microcontroller to feature a serial programming algorithm and EEPROM memory, both of which lend themselves to hobby use: only a simple and cheap programmer is required to program, erase and reprogram the chip. PIC16F84 is a flash version of PIC16C84.
Since then Microchip has released much advanced PIC microcontrollers but this is still very popular among hobbyists. One reason for this is that there are lots of resources available on it and some good books published on PIC16F84. If you are looking to learn PIC microcontrollers, this could be a good choice. You can make your own tutorial board and do experiments. For details, visit this.