It's $5 at Adafruit. The starter pack has a whole bunch of stuff you might want for your first Pi, but probably can scrounge around for free or cheaper.
It's not $5 at Adafruit because the stand-alone Pi Zero is out of stock and cannot be backordered. They'll quite happily sell you a $30 or $50 pack with it in though.
If it's $5 at Adafruit, then how come it doesn't show it? Most of the time a store will list something even if it's out of stock, but will just put a sticker on the entry that says "Out of stock".
The $5 standalone was on their site yesterday morning with an "Out of stock" label. I suspect I wasn't the only person who was annoyed to see that listed next to the bundles, and they removed it because complaining.
I still bought a bundle, because I haven't found any other way to get this in the next few weeks, and the board plus a few basics will be a great <$10 white elephant gift (after I see if I want to keep it for myself).