Yeah, I picked slicing too when F2P, there really is no other choice if you just have 1 slot.
With sub I added artifice and treasure hunting.
Missions from slicing sell good on gtn, as well as purples from hunting. Artifice has been for myself so far. Although now I hope at 400/lvl 50 I can make some stuff to sell. Here's to hoping it will 0_o