TP stands for Training Points and AP stands for Attack Points (it is assumed). TP/AP have been added into LUNA Online quite recently. Their permanence is unclear. Nevertheless, you accumulate TP/AP by fighting monsters. You can then spend AP on extra Skill Buffs just like you would with SP. Skills that can be bought with AP do not require Gold or SP to learn. However, so far, no Attack Skills or other Class-based Skills can be learned through the acquisition of AP.