Does fire kindle have a built in wifi like a smart phone? Can you listen to audio books without wifi?

Yes, Kindle Fire can CONNECT to Wifi. YOU need to have a Wifi network it can connect to. In my house, we have wired internet and we bought our own Wifi router and set it up, connected to the wired network.

If you have a nearby Wifi network you know the WEP/security key for, just try to use the browser and the Kindle should try to find a Wifi network and prompt you to enter the security key if it does not already know it.

Re audiobooks (Kindle Fire ONLY) - if you mean the Amazon ones, yes if you have bought and downloaded the audiobook. This requires an Amazon account w/ a debit or credit card in the account. Don't pick the "Free" option for an audiobook - that is signing up for a $15.95/month subscription to get one audiobook per month.

Once an Amazon ebook or Audiobook is downloaded to you DEVICE, it will be available On Device (the opposite of the Cloud tab). On Device items such as audiobooks and ebooks do not require WIfi to use.

Kindle ereaders have no audio and cannot listen to audiobooks.