GM Ignition Module Tester "Good Score"

So Lisa (FieroChick) and I were on a 2nd honeymoon vacation down on the Oregon coast. We were hitting up lots of little shops taking in the local scenery. We wandered into this little junk store / pawn type shop. I immediately headed for the tool area to see what kind of treasures they had. I come across a plastic tub full of misc electronics, volt meters, testers and such. Then I see a bag with a slip of paper in it. I pop it open and sure enough, it says GM / Ford ignition module tester. Its complete with alligator clips, 9v battery adapter and a giant fold out instruction sheet with 4 different tests for the Fiero style modules. I hold it up and holler at the guy, how much you want for this. He hollers back "what is it" I reply its a wire tester thing.   He says, ah gimme 10 bucks. I quickly whip out the 10 bucks and hand it to him.

I am not sure what the cash value is on this, but to me, its worth a lot more than 10 bucks, I have a stack of modules sitting here that I want to check. I'll use a hair dryer on low to simulate a hot engine bay over a few Min's to make sure they don't fail when they get warm.