Kindle Fire HDX

Kindle Fire HDX

David Paul Morris/Bloomberg

The seven-inch version of Amazon.com Inc.'s Kindle Fire HDX starts at $229 with 16 gigabytes of storage, ads (it costs an extra $15 to get rid of them) and a Wi-Fi connection, ranging up to $424 for one that has 64 gigabytes of storage, no ads and LTE service from AT&T or Verizon.