About EVE ISK
Eve Online ISK (The Inter Stellar Currency) is the currency in Eve. The value of Eve ISK goes up and down according to the demand and supply rules. Eve ISK can be earned by usual mining, running trade route and manufacturing ships. Some optional ways to earn Eve ISK are guarding miner or trade runner in deep space or hunting down pirates and claiming the bounty. Others prefer the opposite, being the pirates themselves and earn more lucrative income. Players spend Eve ISKs to get better equipment, skills, insurance and etc. Often, players look for alternatives to buy Eve Online currency with real money from farmers.
Eve Online ISK Guides
Aside from buying EVE ISK directly, there's always the option to get a decent guide and head out acquiring it yourself. Admittedly, this doesn't compete with the speed and convenience you get when purchasing the ISK directly. On the other side it offers some peace of mind since you don't have to worry about your account and risks associated with the transaction. In a worst case scenario, you are out of the money you spent, but don't suffer any warnings or account suspensions (unless of course you take advantage of bugs and exploits). Unlike World of Warcraft, there is only a limited number of guides available for Eve Online. Killer Guides offers an ISK guide that received decent feedback so far it seems. Other alternatives include a number of free guides posted on EVE forums and communities. Having the definite advantage of being free, the drawback is that it's rather scattered and sometimes provides a lot of conflicting information. In the end, it's up to you what you pick.