The Dude gets promised substantial amounts of money throughout the film.
The Big Lebowski promises him $20,000 to deliver the ransom.
WALTER: Anyway. How much they offer you?
DUDE: Twenty grand. And of course I still keep the rug.
WALTER: Just for making the hand-off?
Maude Lebowski promises him $100,000 to recover the ransom.
MAUDE: I'm getting to your rug. My father and I don't get along; he doesn't approve of my lifestyle and, needless to say, I don't approve of his.
Still, I hardly wish to make my father's embezzlement a police matter, so I'm proposing that you try to recover the money from the people you delivered it to.
DUDE: Well--sure, I could do that--
MAUDE: If you successfully do so, I will compensate you to the tune of 1% of the recovered sum.
DUDE: A hundred.
MAUDE: Thousand, yes, bones or clams or whatever you call them.
The Dude negotiates a 10% finder's fee with Jackie Treehorn, which comes to $50,000.
DUDE: Yeah, well, right man, there are many facets to this, uh, you know, many interested parties. If I can find your money, man-- what's in it for the Dude?
TREEHORN: Of course, there's that to discuss.
DUDE: Does the Pope shit in the woods?
TREEHORN: Let's say a 10% finder's fee?
DUDE: Okay, Jackie, done. I like the way you do business. [...]
Now Jackie Treehorn obviously never intends to pay any of that, drugging and dumping him instead. And the Dude didn't deliver either, because the kid only had the ringer at best.
The Big Lebowski doesn't seem intent on paying, either. And the Dude again didn't deliver, exchanging the ringer for his own ringer.
But by exposing the Big Lebowski's fraud, he did deliver to Maude. So did she keep up get end of the deal?