Money is nice, and we all want to have it. We know it now, and Austen knew it back in the nineteenth century. For this simple reason, money is a motivating factor in a lot of the decisions that we see unfold in Sense and Sensibility. Wealth and inheritance create systems of control and power here, that profoundly influence the personal choices and options of our characters; most of the young people Austen introduces to us are financially dependent upon parents or other relations, and therefore obliged to submit to them, according to the rules of the day. Maybe it's not right, but it's just the way things work in the world of the novel – and we see them attempt to balance the pragmatic need for wealth with their emotional demands throughout the book.
Wealth is ultimately what one makes of it – for example, Edward and Elinor's relatively small income is enough to satisfy them because they don't have expensive tastes.
While marriage purely based on financial reasons is uniformly depicted as negative, Marianne's marriage to Colonel Brandon leads us to believe that Austen was not entirely averse to wealth being an important factor in married happiness.