A bedding or seating product comprising a spring core including at least one border wire and a plurality of coil springs. Each of the border wires is generally rectangular in cross-section to reduce wire costs without compromising beam strength of the border wire. Each of the coil springs may be made of a single piece of wire having a central spiral portion defining a central spring axis and terminating at opposed ends with upper and lower end turns. The coil springs may be arranged in side-by-side rows and columns and be connected with each other at the upper and lower end turns by helical lacing wires.