There's plenty of very expensive software - for example some of the really high end engineering packages I've used, for things like 3D modelling and fluid simul

There's plenty of very expensive software - for example some of the really high end engineering packages I've used, for things like 3D modelling and fluid simulation, can sell for upwards of $5K per _seat_. But again, the value this software adds to the business has to be much more than its cost. A big company will easily spend $500K on software to manage construction materials if it means that it reduces their material wastage on a $1b project from 5% to 2%. I'm sure other people here can provide plenty of other examples.