You only need one Hub account and as David 470 posted, you can use Adsense, Amazon and Kontera on it. You can have more than one account, and still use the same Adsense, etc. accounts. The key to making money is researching keywords that you can write about that get a lot of traffic from sites like Google. Go to adwords.google.com, log in, go to Opportunities, click on Keyword Tool and type in your topic. It will give you tons of ideas and show you the amount of searches for each and the keyword value in dollars. Pick the best one and write a good article on it. Here's the hard part, repeat. The people that are making the real money have a whole lot of really good researched Hubs. Check out the highest rated Hubbers and look at how many Hubs they have. You will find that quite a few of them have upwards of 500. It is a lot of work to get to that point, I know that I am nowhere close, but best of luck!