I think Lizzie indulges in a bit of a double standard here - you're right that she's being inconsistent when she judges Charlotte harshly for marrying for $$, then defends Wickham's efforts to do the same.

She seems to hold Charlotte to a higher standard of delicacy and judgment -that a woman should marry a man who's not just financially sound but ALSO attractive, sensible, and personable. A woman who doesn't adhere to this higher standard "cannot have a proper way of thinking" (Ch 24).