I set up the Arlo 2 and lights with POE with an adapter on amazon...
UCTRONICS IEEE 802.3af Micro USB Active PoE Splitter Power Over Ethernet 48V to 5V 2.4A for Tablets, Dropcam or Raspberry Pi (48V to 5V 2.4A) https://www.amazon.com/dp/B01MDLUSE7/ref=cm_sw_r_cp_api_i_RZYTEbZ3SJSEC
Use these to power the Pi:
https://www.amazon.com/dp/B01MDLUSE7/ https://www.amazon.com/dp/B001PS9E5I/