Originally Posted by dby2k

Applies to all classes.

Well here are some basics of avatars:
There are 5 kinds of avatars in general being Event(lvl1), Normal (lvl 1), High(lvl 30), Rare avatars(lvl 30) and Clones.

Event avatars are usually fixed set avatars like the NPC avatar sets and provide bonuses in between high and rare avatars. Some event avatars can be mixed with high avatar sets, such as the arrogant prince set.

Normal avatars are those really crappy ones you see in the cash shop. They don't have a "set" bonus per say.

High avatars are those avatars you see in cash shops with the level 30 logo on them. You can mix and match any High avatars to form a set which gives a set bonus.

Rare avatars are made by binding 2 high avatars together (or event avatars) and choosing the Random option. They give the highest stat bonuses as well as stat/skill boost per avatar piece. Black Crow set is an example of a rare avatar set. And you can tell they have a complete set if they zoom around town.

Clones are avatars that you can wear over existing avatars to change their properties. Like normal avatars, there are High and Rare clone avatars, denoted by yellow and purple respectively. They can also mix with other avatars to form sets.

There's also skins which you can purchase. In general, it's better to get Event Set skins since they give better stats. Not that important really, just choose a color you like.