For full currency of the site, the one you will use the most will be Aurum, which as said before is earned through posting. Anka tokens are earned through finishing achievements, such as posting 20 times in a certain thread, or you may have received one for dressing your character. You can use these in the token shop.
Pandora tokens are at a limit of 3 a day. The regenerate every 24 hours, and are used in the crane game to play.
Currently the event currency is speckled eggs, and when there is an event going on it can be used to buy things in the event shop.
Runes are the only actual thing you can purchase with real money on the site. Buying runes lets you access the monthly items in archaic antiquity. They can also be used in the yearly shop. Purchasing runes helps keep the servers running, pays for artwork for the site and maintenance and improvements to the site itself.
Also, when events roll around (this one is just ending) you have tons of chances to earn items or the currency of the event to buy the items in the event store, and events happen quite often. Every couple months from what I've seen, there has been 2 since I joined in February.
For starters I would suggest posting a hello thread in the Welcome wagon forum, to introduce yourself and meet more users. From there I would check out whatever your into. There's a forum dedicated to the fine arts, media, games, forum games, discussions and even a general hangout area. I'm probably missing a few but hey XD In the clubhouse you can find a bunch of hangout threads dedicated to different topics or just randomness, some hold raffles or competitions for items or currency
There are quite a few free things in the avatar stores for starters, and there's the crane game in the game section for up to 3 free items a day
you can also earn a few backgrounds and the currency of the site, Aurum, by posting in the forums.