Hmm. Looking at my local AutoZone online, the lowest-price battery for my 2009 Jeep Wrangler would be 89.99. One step up is 129.99. Both of those are brands I've never heard of... Gotta go up 179/189 for AC Delco or Duralast.
For the 2014 Ford Flex, it's the same price points and brands.