Assuming you are not VIP, you'll want to make three characters that will serve some purpose (as non VIP accounts can only make 3 characters).
At least 1 should be a merchant, ideally this won't be your priority character as merchants are a pain to level. your merchant is mainly for selling any weapons, gear, cards and whatever else with vend. Once you make enough money with a faster leveling character you can opt to gear up your merchant for whatever you want to do with it (Note: good genetic gears are VERY pricey if you intend to go genetic).
Your next slot should be used to make your bread winner class. Something that levels fast and cheap like an archer or mage type would be most efficient. Both classes are pretty easily geared with little or sometimes literally no money. Both are good for killing things but archer to ranger (always go trans, the only excuse for not transing is being a baby character) is the best choice as they are the more desired class for leveling and beat out both mage 3rd classes in almost every situation.
Your last slot should be something that you genuinely think you will have fun playing, assuming the previous two characters are not as much fun as you thought. Because if your just playing to make in game money and not having then you are not going to have a good time playing this game. At some point you should try to get VIP either through buying it with real money or doing those sketchy survey for WPE things warpportal offers (Or just make more accounts) to make more characters to fulfill whatever need you have.