If you are searching for ways to add to or replace your current income, there are legitimate opportunities on the internet that can show you ways to do that. How long it takes generally depends on how much time and money you invest and how good of a plan/program you are following.
If you are searching for a regular W2, Health Benefits, 401k type of job that allows you to work remotely, i.e. telecommuting. In my experience, those have been rare. I would advise skeptism on everything until you fully understand what the details are. Buying ebooks and access to "secrets" of internet marketing can get expensive fast.
From my experience, most of these programs have the same underlying theme, regardless of the product or business you have to learn some Internet Marketing. This sounds a little ominous, but it's easier than you may think, but it does take time and cost money to do successfully. Beware of get rich quick schemes and scams. If you are thinking of purchasing something, do some research first.
Use a search engine and see what comes up when you put in the name. Many times you'll find people that have been involved before and have shared their experiences. These could save you some money on things that would just take your money and give little in return. You're wanting to make money not throw it away.
Marketing seems to be the key to the success of most of the opportunities to make money online. In the following pages I have listed the different marketing methods I've found. All the information here is free and will not cost you any money. You'll need that to do the actual work. ;-)