There are several sources of the fly prep, some better than others. If you take a cursory look around Galadon you should find some vendor preps that you’ll find useful and relatively cheaply as well. As you explore you’ll start finding all sorts of useful locations of preps spells/sources, but if you are wondering about specifics most people are receptive to revealing that info in character, in game. Ask around and you should find yourself getting up to speed on that sort of thing much faster than just looking around for them randomly. That said, I’ve found lots of useful things by just wandering around exploring. Just be careful, there are many dangerous and aggressive mobs out there, be ready to flee quickly and try to have some source of recall and teleport on you if things get messy fast. Also, be wary of villagers as a mage, they’ll target you based solely on your class and are well suited to facing off against magic users, especially at lower ranks.