My playstyle consist of leveling 9 classes to gather and HQ materials for each other. I'm currently have 8 LV26-33, with Botany at 24.

I pay nickels and dimes for many of my raw ingredients (guild suppliers), the rest come through Mining, Harvesting, and Hunting for materials. After I reached level 15, had those cross class actions, and wore my own HQ gear, HQs were happening as soon as I had access to new recipes.

Focus on recipes crafting your own gear, craft leves, or supplying GC provisions to keep your exp rolling high, especially if you are HQ'ing your recipes. If you oversupply yourself, that's when the markets come in.

If you want just one craft, I suggest go with the one that correlates to your job. For Arcanists, that's Alchemy. Though majority of your materials will need the assistance of Botany, Mining, and hunting to gather materials.