These are the points earned and used to advance your character. The experience you gain goes towards a
pool that is used to calculate your level. As you gain experience you rise in level which gains you more body and skill points. Newly gained experience is called free XP, which means you have not spent it yet. Free experience you gain can be used to buy skills. Buying things does not cause you to lose experience, but merely reduces the amount of free XP you have to purchase things. Meaning you need to gain more experience to buy more.