Guide for a new player in Aion - beginner questions

I am willing to give a try to this game. I don't know anyone that plays it , so I've started to research it on internet. Even so i have a few questions. All I'm interested in this game is the PvP.
So here are the questions :
1.Anyone can explain me witch are the advantages and disadvantages of the classes ?
2.Witch is the most indicated class ( or better if there is such thing ) for PvP , I could not decide that from the movies and all that , and i don't want to grow up 3 chars
3.How can i pay the game ? Is it possible only with the card ? I know in other games you can pay with the game money for example selling items to other in exchange to game time cards.
4.Any suggestions for a good server ?
5.How much time you need to spend in game if you wanna be good in pvp ?

Thanks in advance , i hope someone will be able to answer my questions

I will try to answer you ...
1. Classes are relative , i mean what matter most it's if you know how to play , your equipment and then of course what you enjoy playing more - tank , healer , melee dps , range dps
2.Well , it depends a lot where you are doing the pvp , classes have advantages and disadvantages depending on the zone. For example in abyss where you can fly , the best are the rangers and the sorcerers , but if you prefer 1 vs 1 fights then maybe a assassin would fit better for you. Spiritmaster and the Cleric are rare tho.
3.The only methods to pay the game is either to buy game time card from shops , or to pay with credit card the subscription.
4. It a lot more easy to play and lvl if you play with someone that helps you. All servers got gold sellers and boots.
5. I for example play like 3-6 hours / day , it's depending on my drill. Like in any game , longer you play as better you get.

Hope I've been helpful

I don't know Aion, but I've played several mmo's and I'll tell you some general tips:

- classes doesn't matter...some have advantages early game, some late game
- try to keep your gold for higher levels
- do quests solo and party (whenever possible)
- grind whenever you feel bored (for extra xp and gold)

From what i see , i think i will go for the assassin , it more my type