Using jquery: for example, when describing benefits, if there are like 15 benefits and we just want to show the title of them, and then when clicked, we show the sum of each, js would be the best way to do the trick right? Is it possible to use jquery in unbounced.com landing pages to solve this kind of issues?
Yes you can use JQuery on an Unbounce page. If there is a button, text or a from component on your page then JQuery 1.4.2 is already automatically included.
If you want to target specific elements with jQuery selectors then you may need to look at the html source of the page in either the page preview or the published page in order to see the ids that are generated by the Unbounce editor for the various page components.
Down the road, we plan on allowing custom css classes to be added to Unbounce components to make this sort of modification easier.