Made for an art trade with
Boba bought Ahsoka at the Togruta slave auction (based on the newest Clone Wars comic where all the togruta (Ahsoka's race) are all put in a slave auction and Ahsoka actually does wear that exact outfit: [link]
<--- proof in that link)
So, in my version of the story, Boba Fett somehow bought her and got away before Anakin could stop him, hahahahaahaha.
AHSOKA IS NOT HAPPY ABOUT THIS!!! Boba is pretty happy about this.