Building a successful and sustainable online business is going to take some combination of time and money. One of the beauties of Internet marketing is that you can start a sustainable, successful online business with very little money at the beginning. But that means you'll need to devote a lot more time to make up for it, by learning how to do a lot of things yourself that you could pay other people to do.
Eventually, as your business grows and the money starts to come in, you gradually outsource many of the tasks you did in the beginning to free yourself to focus on the bigger picture. But in the beginning you'l probably be doing everything by yourself.
On the other hand, if you have a lot of cash reserves that you can invest to get started, you can save a lot of time by finding a suitable Internet marketing mentor. You should take some time and choose carefully, as there are many people offering mentoring and coaching services, and their qualifications and abilities range all over the map.
Your best bet is to find a place like the Warrior Forum, one of the biggest and most respected marketing forums online, and become familiar with the members who call themselves Internet marketing mentors. Read their posts, see what they contribute, and what their areas of expertise are. If you find someone with a personality and skill set that feels compatible to you, contact them if they're not already advertising coaching or mentoring.
If you're on the other end of the spectrum -- that is, with more time than money -- you probably shouldn't be looking at an expensive Internet marketing mentor. You definitely should not spend more than you can comfortably afford. Don't spend your rent or food money thinking you'll be able to earn it back quickly, because it rarely works that way.
Another option to explore is lower-cost membership sites that offer expert guidance and the moral support of other people who are in the same place as you. For instance, I'm part of a membership site called Online Business Insiders, where a group of experts who all make a full-time living online tutor beginners by showing them their business models.
The membership route is a good balance that doesn't cost much, but also saves you a huge chunk of time if you tried to learn it all completely on your own. In the end, you'll need to weigh all the factors and decide whether an Internet marketing mentor is for you or not.