In Great Expectations, how does Pip in the second stage deal with his money?
The simple answer is very badly. In spite of his "great expectations" and the amount of money that he has at his disposal, Pip himself confesses that he turns into something of a spendthrift, wasting money on drunkenness and dissipation, in particular joining an infamous group of young men called The Finches, which helps contribute to his profligate ways. In addition, he admits with some shame that his spending habits leads his friend Herbert to imitate him, which causes Herbert to fall massively into debt. Of course, for Herbert, without the same kind of resources that Pip can draw on, this is a much greater difficulty than it is for Pip. Note how Pip summarises his relationship with money in Chapter 34:
We spent as much money as we could, and got as little for it as people could make up their minds to give us. We were always more or less miserable, and most of our acquaintance were in the same condition. There was a gay fiction among us that we were constantly enjoying ourselves, and a skeleton truth that we never did. To the best of my belief, our case was in the last aspect a rather common one.
Note the element of self-deception that Pip alludes to in this quote. Even though their state is described as "miserable," the "gay fiction" of having fun forces them to ignore the "skeleton truth" of the reality of their situation. The rather ironic final sentence comes from the older Pip looking back at his youthful misdemenours and commenting on the way in which so many young people experience similar pressures and issues. Having money has turned Pip therefore into a prodigal and profligate character.