Not sure where the best place to post a deal is so here it is. Phantom 3 batteries are $99.00 on Amazon today. They are shipped direct by Amazon, not a third party seller, so they should be genuine. I was able to get B&H to match the price (I had a gift card).
https://www.amazon.com/exec/obidos/ASIN/B00Y1W5EEU/ph079-20
https://www.amazon.com/exec/obidos/ASIN/B00Y1W5EEU/ph079-20