1) Tony - Hesh estimated his net worth at under $5 million (and he scoffed at this, as a boss should be richer). This was during his period of big gambling. By the end of the series it is reasonable to estimate that he has around $5 million put away. Even if it's just $3 million, that's plenty of money. Given that he was a boss, there were plenty of people kicking up to him that we never saw. Also, he never had expensive trials.
Actually, Hesh said he thought that Tony "Minus assets, was under 6" - meaning $600,000. In other words, once you took away the house, cars, and other assets, Hesh figured Tony had maybe $600k in liquid cash. This, he figured, was largely due to Tony spending it as fast as he made it. Tony was a millionaire but much of it was tied up in property and what not.
The same thing could be said for Johnny Sac, who's total net worth was estimated at $5 million.
It was one of those things that made The Sopranos very realistic. These guys didn't have that mythical "Don Corleone money." Guys who reached the upper levels, like Tony, Johnny Sac, Carmine, etc. had some good money, but it was in the 7 figures. And could quickly vanish when business wasn't going so good. And most of their guys - the average mobster - was more or less middle class.
