Your best bet is to look in your phone book under cement, sand and gravel. You can get it much cheaper and you may also have a choice of fine sand or coarse. If you have access to a pickup truck, a small PU can haul half a yard for around $20 for the load or a large PU can haul one yard. I'm sure five pounds of sand from a building and garden supply will cost you that or more and you'd only be getting a tiny fraction of what you need. Most of these gravel yards will also deliver for an extra charge.
I prefer masonry sand. It is fine sand but has an assortment of larger gravel in it that the chickens use as grit. Lately, though, I haven't been able to get this sand where I live so I have resorted to ordinary construction sand. It's very cheap, but also quite coarse.