Every other classical Indian school has its own texts to speak from. Charvaka does not. No complete work by a self-declared materialist survives, and almost everything known about the school's positions comes from the opponents who quoted it in order to refute it, Vedantins, Naiyayikas, Buddhists and Jains.
What survives anyway is a coherent and radical position. Charvaka, also called Lokayata, admitted only perception as a source of knowledge and rejected inference outright, on the grounds that inference depends on a general rule, and no amount of past observation can prove a rule will hold in a case not yet observed. Testimony fell with it, since testimony is only as good as the inference that the speaker is honest. Stripped of both, the school had no way to argue for gods, an afterlife, karma or rebirth, and concluded, consistently, that none of them exist. Consciousness, on this view, arises from the combination of material elements the way intoxicating power arises from fermented grain, and ends when the body that supports it does.
The most systematic surviving account is a fourteenth century one, a chapter in Madhava's Sarva-darshana-samgraha, A Compendium of All Philosophical Views, which walks the reader up a ladder of increasingly correct schools, with Charvaka placed deliberately at the bottom rung. A separate figure, the skeptic Jayarashi Bhatta, wrote the Tattvopaplavasimha, using materialist arguments to attack every means of knowledge in turn, including the ones materialism itself would need. Whether Jayarashi counted himself a Charvaka or had gone further into a skepticism refuting materialism too is still argued about. Both figures show a genuine current in Indian thought arguing that Vedic authority, karma and rebirth were not self-evident.