Raspberry Pi Zero v1.3 - https://www.adafruit.com/products/2885 - $ 5.00
Tiny USB OTG Adapter - https://www.adafruit.com/products/2910 - $ 2.95
16GB Micro SD card - Many Sources - $ 5.00 - 10.00
Smallest WIFI USB - https://www.adafruit.com/products/814 - $11.95
LIon Battery 3.7V 2500mAh - https://www.adafruit.com/products/328 - $29.50
PowerBoost 1000 Charger 5V -https://www.adafruit.com/products/2465 - $19.95
5V 2.4A 6' MicroUSB Cable - https://www.adafruit.com/products/1995 - $ 7.95


Optional
---------------------

USB wifi (802.11b/g/n) with antenna - http://www.adafruit.com/product/1030 - $19.95

USBHub 2.0 Powered/7 Ports/5V 2A Power Supply - https://www.adafruit.com/products/961 - $21.95
StereoFM Transmitter w/RDS/RBDS Breakout https://www.adafruit.com/products/1958 - $19.95
CZERF 76-108MHz 1W FM Transmitter/power supply/antenna - https://www.amazon.com/CZERF-76-108MHz-Transmitter-station-Professional/dp/B00S26BKM6/ - $53.89