税込 (zeikomi) means tax included. Bandai's Japanese item pages write prices such as 3,960 円(税10%込), with Japan's 10% consumption tax in the number.
Bandai's Japanese page for the MG 1/100 RX-78-2 Gundam Ver.Ka reads 3,960 円(税10%込).
Read Oct 14, 2026. The definition is ours; facts come from the pages above.