In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Black pipe is used for gas, steam, and forced hot water heat; galvanized pipe is used for waste water, and domestic water [the latter not so frequently now, but once was the standard]; copper tube is used for domestic water below grade[type K], domestic water above grade [type L], forced hot water heat [type M], and waste water [type DWV]; plastic is used for waste water, pool lines, forced hot water heating [pex], and in some locations for water distribution; brass was used for water distribution, but now it has become costly and copper took it's place in that market. All the above you'd find in a residential application. Commercially you'd see stainless, glass, aluminum for all kinds of processing [milk, soda, etc.] bwdik?ijap