According to dictionary.com, the definition of the word conservative is "disposed to preserve existing conditions... and to limit change", while the definitions for liberal include both "favorable to progress or reform" and "open-minded", "tolerant", and "not bound by traditional or conventional ideas". The point of note here is that the definition of "conservative" does not include "closed-minded", however, in modern thought, this definition seems to be implied. Conversely, the word "liberal" does not mean "revolutionary" though more than a few might disagree with me.
You will note here that neither term comes with any sort of financial connotation. Liberal does not mean "out to discharge the contents of the public coffers for 'the greater good' at the drop of a hat" nor does conservative mean "willing to part with the blood and lives of 'the underprivileged' rather than spend a dollar to help them". So, why do we use those terms to describe a person's financial tendencies?