How about making money online without having to sale any products?
Yes, it is definitely possible with content publishing business model. You will need to write content and publish it on your website, the content has to be centered around a targeted keyword, once the web page is published, it has to be optimized with the targeted keyword so that the page will rank high in search engine result page when the keyword is being searched for, thus drawing visitors to your content site.
How would you monetized from the visitors then? Well, one of the easy ways is by putting up Adsense codes, which means, content publisher will allocate some space on their web page to display Google’s advertisement, once the code is inserted to the page, Google will automatically display ads which are relevant to the content on the web page, with such relevant ads, visitors may click on them to get more information related to the content they are looking for, and once the visitor click on the ads on your page, Google will pay you accordingly, the amount of payment ranges from few cents to few dollars per click, depending on what ad is being displayed and how much the advertiser is paying for the ad.
When publishing a content website, different web pages each with different keywords under the same theme will be created, the more web pages being published, the more keywords will be optimized for the search engine, thus increasing the changes of getting one of the pages of being searched and get ranked.
In case if you are not keen in writing the content your self, you can always out source it to third party writer, sites such as elance.com, rentacoder.com etc has many writers where you can post your assignment to them and negotiate for the price.