Complex sentence: Weller continued to produce fine art wares until the beginning of World War I era, when Weller turned to commercial art wares, which were cheaper to produce, as they were molded, with few if any artistic additions.
Split into simpler sentences: Weller continued to produce fine art wares until the beginning of World War I era, when Weller turned to commercial art wares. These wares were cheaper to produce, as they were molded, with few if any artistic additions.