The biggest expense is the Cabinetry.  Custom kitchens usually include features in the cabinets for storage, organization and furniture details.  You can expect the cabinets could be 30-40% of your material allowance.  The lower your Material Allowance the greater the % that will go to cabinets because there is no way to cut cabinet cost without cutting quality or features.  Appliances come in second highest at 20-40%.  Countertops 10-20%.

image via our custom cabinetry supplier Dura Supreme