Wouldn't Wentworth also draw a salary as well as being able to keep any prize money? That should be added to his income as well.

I don't think Wentworth is the poorest. I don't think we have exact figures on all the heroes wealth (some, such as Knightley, only have very good educated guesses.)

Edward Ferrars at the end of S&S is looking forward to an income of around $700 a year (with some chance for improvement.) Elinor who is very practical about money, is satisfied that this will be enough to live on.

I can't remember how much Henry Tilney's living makes, but I believe that's the sum total of his income. For some reason, $1,000 ppa, sticks in my head.