They're not self-centered materialists by any means.
彼らは決して自己中心的な物質主義者ではないのです。
" by no means " を使って、 " By no means are they self-centered materialists. " あるいは " They 're by no means self-centered materialists. " と言い換えることもできます。また、 " by all means " は承諾の意を強めて「ぜひどうぞ」「結構ですよ」という意味です。