(Disclaimer: I didn't check every Instructable to determine if this has already been presented (there's just too darn many). If this is a repeat, I apologize.)
Some time ago a test lead on my el cheapo multimeter came off and was subsequently lost. Using the frayed ends of the lead wire worked, but not worth a hoot.
I visited our local Radio Shack and a couple of other shops to find a replacement lead but the cheapest I could find was $6.95 (US) for a pair; I could have replaced the whole thing for that.
Step 1: Step One
A 6 penny finish nail, an old pen barrel sans ink "tube," soldering iron and solder (not shown), a bit of heat-shrink tubing, an X-Acto knife (or substitute) (not shown either) and our favorite, a hot glue gun and glue (also not shown).
I measured the ink barrel against the non-broken test lead for length then cut the barrel to length (measured from the tip). Save the cut-off end of the barrel as this will make good filler in your extra parts box.
Step 2: Step Two
Step 3: Step C
I then hot glued around the wire end, filling up some of the ink barrel. I also shot a small dab of hot glue around where the lead protruded