$8.97 (as of January 10, 2017, 12:53 pm)
ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM
Mini-USB jack for power and/or USB uploading, you can put it in a box or tape it up and use any USB cable for when you want to reprogram.
5 GPIO – 2 shared with the USB interface. The 3 independent IO pins have 1 analog input and 2 PWM output as well. The 2 shared IO pins have 2 more analog inputs and one more PWM output.