Hmm, I thought it was five cents, but it looks like four. I'm not sure it's every time, but certainly the first time.
As of today, 1011 people have downloaded "Biographical Notes..." and 2505 have downloaded "Embracing-the-New". The next runner up is "Droplet" with 34 downloads. That disconnect between free stuff and stuff that costs a smidgen is the internet in a nutshell, right there.