I find Target brand diapers to be just as cheap as the Luvs diapers and they both are good absorbent diapers for the price.
If you need cheap baby diapers I would recommend either the Luvs or the Target brand.
You might have to try different brands of diapers on your child because some brands of diapers work fine for one child while other brands don't work as good on that same child but will work fine on a different child.