Some people might accuse Charles Dickens of being too idealistic and naïve when he talks about poor people. After all, some of the poor characters in his novels are incredibly beloved by readers (we're looking at you, Oliver Twist).
But Silas Wegg is here to remind us that Dickens didn't necessarily think poor people were nicer than rich ones. The truth is that Dickens thinks you can find both horrible and angelic people anywhere, whether they're poor or not.
The first thing we learn about Wegg is that he never lets anything slip past his notice. As the narrator tells us,
Mr. Wegg was an observant person, or, as he himself said, "took a powerful sight of notice." (2.5.6)
On top of that, he always knows how to get the most out of any situation. Even after Mr. Boffin offers him a cushy job as an evening reader, Wegg wants even more from the man and asks him for food in addition to his usual pay. In one pretty hilarious scene, he asks,
You read my thoughts, sir. Do my eyes deceive me, or is that object up there a—pie? It can't be a pie. (2.1.135)
Of course he knows it's a pie… and that he'll be having some.
As the book unfolds, Silas Wegg goes from being a funny street vendor to one of the book's main villains. Once he has taken up a position living in the house of nice Mr. Boffin, Silas Wegg feels like it's impossible to sleep "without first hovering over Mr. Boffin's house in the superior character of its Evil Genius" (12.7.95).
In other words, Wegg is completely self-interested, and he's willing to play the part of the villain if it means getting as much for himself as he can. Luckily, he gets his just desserts in the end when Sloppy drags him out of Mr. Boffin's house by the collar and tosses him into a garbage cart.