Amanda Bynes -- On the Loose ... and Hunting for Wigs

Beware citizens of Gotham, Amanda Bynes is among you.

Not long after firing off a bizarre tweet of side of her arrest story, Bynes was picked up by a car service this afternoon and driven out of her NYC apartment building.

Our photog was only able to spot Bynes for a brief moment before she jumped in the tinted SUV ... and says the former actress ditched her blonde wig for a black one.

According to our spies, Amanda hit up a wig shop in the West Village. We're told she tried on a few blonde ones, but ultimately decided against purchasing any when the commotion from all the paparazzi became too much for her.