You can replace an extension cord plug yourself.

Yes, but do it carefully. It’s not hard, but electrical work has zero room for sloppy assumptions.

The damaged plug usually gets cut off. Buy a replacement plug (the heavy-duty “molded” type meant for repair) from a hardware store. Make sure it matches your cord gauge (e.g., 14 AWG or 12 AWG). Turn the cord into something vaguely manageable: cut the old plug off cleanly, then strip about ¾ inch of the outer jacket and each wire.

Match the wires to the new plug terminals. For a standard US 120V plug, the brass screw is the hot (black wire), silver screw is neutral (white), green screw is ground (bare copper or green). Wrap the wire clockwise around the screw, tighten, double-check no stray strands are touching the other screw. Then close the plug body snug.

One non-negotiable: disconnect the cord from power before you start. Obvious? You’d be surprised. Also, never use a lamp-cord plug on a heavy-duty extension cord — the amperage rating will be wrong and it’ll overheat.

If the cord itself is frayed, cracked, or has exposed wire farther back, toss the whole thing. Don’t patch a cord that’s already failing.

This is not where you save six bucks. A new cord costs $10–15. But if you’ve got a good heavy-gauge cord with a busted end, a $4 plug repair is worth doing right.