The God and mammon video made some good points. You're right about lots of 'religious' people demanding money or abusing religion to defraud the unsuspecting. But this has been going on for a surprisingly long time. You know the way you sign off a letter with 'yours sincerely'? Ever wonder the origin of that phrase? It comes from pagan times (in the Roman empire) when vendors would hawk little statues of the various gods outside shrines. Now the 'proper' statues would be made of gold or silver, or perhaps at least a base of copper with a generous coating of silver for the cheaper ones. But even copper and tin are expensive so the really unscrupulous used-car salesmen of teh statue trade found a way to make an even bigger profit. They used hardened wax as the base with a thin coating of gold or silver over. Very cheap, and a tidy profit. Of course it wasn't long before this trick came to be known and people were wary when buying their votive statues. So vendors would put up signs telling their prospective clients their statues were without (sin) wax (ceres) = sincere (latin). This word has come down to us through time to mean 'without deception' or 'honestly'.

In the middle ages the abuses of selling pardons and indulgences was well-known. Chaucer roundly mocked the vendors in his stereotypes in his Canterbury Tales (see "the prologue to the Pardoner's tale", plus the tale itself). It was one cause of the schism with the Vatican that led to the reformation.

But we find people in all walks of life engaging in such dishonest practices. I remember reading of a sociologist who wasted 18,000 dollars of tax payers' money in the form of a grant form his university. The title of his thesis / research? I don't remember it now exactly, but it was along the lines of 'the interpersonal relationships found within a Peruvian brothel'......

Since you've read the New Testament you'll be familiar with Jesus' approach to money. Apparently He didn't even own a purse into which to put it. Judas (Iscariot) was the one who took care of all the finances. Jesus warned the Apostles 'carry no purse, no haversack' but told them to accept such help and support as people offered graciously (no hint of extortion). He drove the money lenders and merchants out of the temple in a very rare burst of righteous anger accusing them of turning His father's house into a den of thieves. My feeling (without wanting to slander anyone genuine) is that much of this televangelism today is along the same lines as those merchants.