Is prayer like money?

I don't believe that prayer works, but I'm interested in a Christian perspective on this one. What is the difference between one person praying and millions of people praying. God will hear each of them just the same, and if their prayers are heartfelt and faithful, then why wouldn't he answer them just the same. Why should we constantly pray for souls in purgatory? Couldn't someone have said one prayer to help get all the souls who would ever be in purgatory to Heaven? As long as you have faith, why should you say ten Our Fathers instead of just one. To me, prayer circles and petitions for prayers at mass seem like prayer has become money in that the more you have of it, the better the chance that God will hear you and answer your prayer. I just don't understand what the point is.