My mother told me not to waste that money.

Literal

Mother [topic-は] me [to-に] that money [object-を] waste-not [indirect-command-ようにと] said

無駄遣いしないようにと言った = 'told (me) not to waste it.' 無駄遣い (むだづかい) = wasteful spending. Negative + ようにと = indirect prohibition.