Exactly, this. It's hard to be truly anonymous. But I have considered one day modding a satellite dish + network adapter to use the local library's WiFi instead (or the neighbors' if the library's walls are too thick). I've heard of people doing it and it seemed interesting at the time, but I can't find any cheap dishes on my local Craigslist.

EDIT: Just to clarify, I agree with the use of untraceable currency and an e-mail address not linked to your identity when you're signing up for services where you want anonymity.