The problem with starting with the least expensive cables is you'll choose components, maybe even speakers, that are complimentary to the cables flavor. If you start with neutral cables then your component choices will probably be better, i.e. more neutral as you're not compensating for a warm or bright cable, resulting in a better system. So, I agree you want cables that do as close to nothing as possible but this takes a decent cable. Good cables and clean AC power are the backbone of a system and make it possible to assemble a better system and evaluate components more realistically.
Also, used cables may be cheap but MSRP is a often a fairy tale anyways... better to know a bit about cables and select the most neutral cable you can afford.