I really love shopping at Harbor Freight. Although they don't necessarily have the very very best deals on everything, they carry tools that are impossible to get at any other consumer-level retail store. And unlike discount stores, you can usually get JUST what you want, not a blister pack of 24 associated tools.
I was very pleased on Saturday when I went down to the Big City to see Coraline in 3D, we stopped by Harbor Freight on the way. In the front of the store, they had a bin of digital multimeters:
for THREE DOLLARS. Usually they would cost ten times that at any store. I bought four of them. I took one out of the packaging and it works.
I'm going to be putting together a tool box for each of our cars, and I'll put a multimeter in each one. They're incredibly useful, and that way I won't be without one wherever I go.
They're an infinitely useful tool if you every work on anything electrical, or on cars, or really anything.