People who are economically poor are well aware of their need. It is very likely that, if they pray at all, they pray for money, for prosperity. One does not need to have a revelation from God to see that kind of need. But what should the poor be praying for? They ought to be praying for the desire to work, for the understanding of their responsibility to their families, for the right kind of ambition that will motivate them, for the love that will make them lay down their lives to support their dependents, and for the drive that will energize them to find a job. These are the things God wants us to ask for because they are qualities that He has. By nature, we like to short-circuit the process and pray, "God, give me money. Give me a job." He would rather we ask for these other things, and He is far more likely to respond to us when we do.
The poor in spirit are the best prayers of all. Their title, "poor of spirit" or "poor in spirit," shows that they are people who properly evaluate themselves against God. They see how rich God is in terms of love, generosity, kindness, mercy, wisdom—all the good qualities—and they see how poor they are in comparison. Wanting to be like God, they askHim for the qualities He has. Those are the kinds of prayers God responds to. In contrast, the proud will not be good at praying because they are secure in themselves, unable to see their need.