Making your own liquid soap is easy, and all you need is bar soap to make it. It works best with moisturing soap, but you can also use the trendy scented glycerin soaps as well.
Take the bar of soap and grate it into a bowl. Add three cups of warm water, and microwave on high until the soap is melted, stirring regularly (every minute). Allow to cool and then pour the new liquid soap into a pump dispenser.
For the pump dispenser, you can either use an old soap dispenser you have cleaned, or you can often buy new unused pump dispensers that are perfect for liquid soap at the drug store or dollar store.