For a standard single-gang plastic box replacement, the combined price typically falls in the $100-$350 range when no extra work is required. If the box is metal, deeper in-wall, or requires wiring re-run, the price commonly rises to $350-$700. Junction box costs range from low‑price indoor models ($10‑$60) to weatherproof units ($70‑$450), with installation averaging $100‑$300 depending on location and materials. The final price depends not only on the box itself, but also on. The retail price for a junction box varies widely, directly reflecting the material and specialized features needed for the application.