Well, that makes senseLuke 16:8b-9 are Jesus' words following the Parable of the Dishonest Steward:
"For the children of this world are more prudent in dealing with their own generation than are the children of light. I tell you, make friends for yourselves with dishonest wealth, so that when it fails, you will be welcomed into eternal dwellings."
If on Friday you had asked me for my thought on this passage, I would have said something like, "Oh, you know, sometimes Jesus is inscruitable. Semitic idioms, and all that."
Now, though, I'd be ready for you. "Have you not read," I would reply with butter-won't-melt sincerity, "the notes on these verses in the NAB and the Douay Rheims?"
The...conclusion recommends the prudent use of one's wealth (in the light of the coming of the end of the age) after the manner of the children of this world, represented in the parable by the dishonest steward.
The DR, which has "mammon of iniquity" instead of "dishonest wealth," says:
Mammon signifies riches. They are here called the mammon of iniquity, because oftentimes ill gotten, ill bestowed, or an occasion of evil; and at the best are but worldly, and false; and not the true riches of a Christian.
As for the friends made, the DR notes that they are
the poor servants of God, whom we have relieved by our alms, [who] may hereafter, by their intercession, bring our souls to heaven.
The solution, then, presents itself once you allow "prudence" and "wisdom" to be generic terms, that can be used relative to either temporal, human ends, or eternal, divine ends.
The dishonest steward was prudent, in this generic sense, because he did something that would accomplish his end of having people who would feel obliged to look after his temporal needs. Jesus tells His disciples to be prudent in doing something that will accomplish the end of having people who will look after their eternal needs.
And it so happens that both the children of this world and the children of light can use plain old everyday money -- dishonest and iniquitous, at the very least, in the sense that sooner or later it will fail to get you what you want -- to set themselves up for the future. What Jesus is saying, in part, is that the children of this world know this and the children of light do not.