How does Shakespeare use money, such as pounds, as a reference to create humor in Twelfth Night?

There are a few different places in which
money, such as ducats, coins, or
pounds, is used as a reference to create a comic
effect.

The first place is when Maria quizzes Sir
Toby about bringing Sir Andrew into the house to be a suitor to Olivia. Toby
defends his position by arguing that Andrew is as "tall a man as any's in Illyria," which is
apparently an attempt at making a case for Andrew's looks (I.iii.18). When Maria catches the
weakness of his point, asking, "What's that to the purpose?," Toby reveals his real
reason for inviting Andrew into the house as a suitor, saying, "Why, he has three
thousand ducats a year," which is a comment on Andrew's salary,
showing us that Toby really just wants to get his hands on Andrew's
money (19-20). This revelation is comical in the sense that it is
also ironic. It is ironic that Toby wants Andrew to court Olivia so that Toby can
access Andrew's money. Normally a suitor's money would have nothing to do with his so-called
friend; the money would belong to the suitor alone, and should he marry, he could choose to share
it with the bride. Hence, the fact that Toby is trying to set Olivia up with Andrew so that Toby
can access Andrew's money is both ironic and comical.

A second
comical reference to money is when Viola as Cesario pays Feste for entertaining
her with his plays on words. He next asks for a pair of coins so
that they might breed, saying, "I would play Lord Pandarus of
Phrygia, sir, to bring a Cressida to this Troilus," which is to say that he would act as a
"go-between" to help pair a female coin with his male coin so they might breed, just as Pandarus
of Troy acted as a "go-between" to join Troilus and Cressida together (III.i.49-50; title="William Shakespeare, Twelfth Night Or What You Will, ed. Kenneth Deighton, Shakespare
Online, shakespare-online.com"
href="http://www.shakespeare-online.com/plays/twn_3_1.html">Shakespeare-online,
Twelfth Night). This is also comical because
his idea about breeding coins to make more coins is, of course,
ironic. Coins cannot breed together to make more
coins.

A third place in which money is referred to
in order to create a comical affect is in the final scene. Just after Sebastian hurts both Sirs
Toby and Andrew, Andrew exclaims, "I had rather than forty pound I were at home," meaning he
wishes he were home rather than having his last remaining forty
pounds (V.i.185). The irony is that we know very well
Sir Toby has been draining Andrew of his money, and if he had staid
at home instead, he would not be down to his last remaining forty pounds. Hence, even this
reference to money is comical due to its irony and is also revealing
about the characters.