This is a short answer forum, but I'll see if I can give you a few ideas. As far as money changing someone, you might use Pip's character. After being a part of Miss. Havisham's household, he gets big ideas, which are dashed when she pays Joe for his indenture. None-the-less, Pip miraculously gains a benefactor, something that causes him to be embarassed of his roots, and the people who love him. His behavior toward Joe is inexcusable, and his behavior toward Biddy..... anything but gentlemanly. Instead of being careful with his money, he goes into debt, and doesn't learn what a true gentleman really is until he understands why he has been so fortunate.
On the other hand, we have Magwitch. I love his character. He's been swindled, manipulated, and imprisioned, but even after his escape, he gives the little boy who helped him the chance at a future he never had. He asks nothing and questions nothing; he could have kept his money in Wales, never to return and lived like a king, but he didn't.