Can't find element by class selenium amazon

I am currently trying Selenium Webdriver on the amazon.es webpage. I have successfully navigated through the webpage, looking for an element by class (the search item button to be precise).

The problem is when I try to get the prices of the webpage. The webpage can be found here (just look for Balon Baloncesto=> Basketball). When I try to search the element by class, this one exactly:

<span class="a-size-base a-color-price s-price a-text-bold">EUR 33,64</span>

Selenium cannot find it, giving the not found element error. Here is the Java implementation. nav is the browser object.

//value = a-size-base a-color-price s-price a-text-bold
elemList = nav.findElements(By.className(value));
//elemList appears to be empty after this

There are not any iFrames on the webpage which can affect me, so I do not get very well where can the problem come from. Any help would be appreciate it.

Best regards