How much does building a church cost?

Today, at work, I overheard two men talking, and one said; it costs a lot to build a church. That got my attention; it does not cost anything to build a church, I replied. The other man went into how much stained glass windows cost to make, and I could not comprehend why anyone who speaks for God, or in the name of God, needs stained glass windows. So, I replied; churches are within, and stained glass windows or any other luxury is not required, just a person, the self. They understood what I was saying, but the second man responded people are used to tradition, this is what they are used to when they pray. Just like some religions have staue and according to others it is wrong to have them, but they do not know the meaning of them is to honor them. I am still confused; do we need exensive statues to honor saints? Why not honor ourselves? Why not honor each other? If church works for you, great, but does it have to be an expensive building? Do we really need to keep up a materialistic tradition?