Personally I would recommend against cheaping out on Lithium batteries, who knows what they did to lower the price, could be a safety hazard, these are what I would recommend
Samsung INR 18650 35E 3.7V high drain unprotected flat top battery (pink wrap) is one of the well balanced 18650 batteries on the market that can handle current at 8A & large capacity of 3500mAh.
I second Reg's recommendation. You don't have to buy the exact cells from the BOM, but for your safety you should ensure that you only buy legitimate cells from a reputable manufacturer like Samsung or Panasonic. Vapcell (not a spelling error) is a newcomer brand that has also tested well so far, and can probably be trusted.