Does organised religion prey on the vulnerable and exploit the weak?

Yes, but not intentionally.  Granted "organized religion" includes a number of religions and there are some that definitely try to exploit weakness and vulnerability.  For example my grandfather's funeral was done in  JW assembly and it was mostly an attempt to convert us "heathens" to their faith, rather than providing comfort or honoring his memory.  A different example is that while most Christian denominations/sects are firmly against "missionary dating", Mormons encourage the practice.

True religion is free. The cost was already paid by Christ Jesus when He defeated satan 2000 years ago.

 Professional religions do exploit indeed. But there are some that ask only for help (sometimes only volunteers) to help others in need, and to help missionary Christians to go to other places to teach the teachings of Christ.

 Christ said, "By their fruits you will know them".  Which means in this case that you have to learn for yourself how that money is being spent by any certain Christian group before you give any cash over.

Not generally, no.   But there are always some scammers.

Oh please if that were the case the biggest religions would be rocked by sex issues involving children and financial corruption preying on widows.

Clearly groups like the Catholic church, scientology, LDS church the biggest most successful religious organizations have never had those issues.

The religious mind is primed to accept lies. Presented with an extraordinary claim, it does not demand extraordinary evidence, but instead engages faith to overcome skepticism. Their religion has taught evangelicals to accept, rather than to question. Trump’s constant waterfall of outright lies landed on amenable minds. His support was greater among regular churchgoers than among lukewarm believers. The greater the faith, the more subordinate healthy skepticism becomes. So the biblical fetish for totalitarians may have helped America elect its first.”

― Andrew L Seidel, The Founding Myth: Why Christian Nationalism Is Un-American

Yes.

Cults do that; not any of the mainstream religions.

Organized religion prepares you to go to hell, to conquer that dimension!

No. I think if that was the case churches would be full of the lower classes of society. What i find is it's the middle-upper classes who generally to church and are also the biggest givers. 2 theories on why. Some genuinely do believe. And for others, its a way to satisfy their moral side. If they go to church, they have to be good people if that makes sense. I think if you walk into a church and meet the people, especially the more modern mega churches, the make up may surprise you.

I also think this class of people is why they get away with so much. Middle-upper classes know how the world really works. They've seen the stretching/breaking of ethical norms in day to day life and in the business world so are more likely to overlook the church's pushing these boundaries. Ironically the lower class or student population, especially the newest generation, would be more likely to take a stand.

Definitely.   They zero in on the lonely, the bereaved, and those facing difficulties and love-bomb them as an insincere way to suck them in.

YES          Religion is a scam.