Ditto to the above.
Sears also has a selection of digital multimeters, some of which look like Flukes, or knock-offs thereof, not too expensive either.
Things to look for are high input impedance (all modern digital models have this), "bounce proof" case or add-on rubber guard, and get one that measures amps too.
BTW, Radio Shack has this cool little pen-style solid state oscilloscope gizmo for $80 that you can use to see time dependent stuff like crank sensor outputs, injector firing durations, points, encoders, etc. Their P/N is 910-4905, and you have to order it thru the catalog. The gizmo is actually made by Wittig Technologies:
http://www.wittig-technologies.com/english/05_products/01_oszifox/oszifox_01_intro.htm
I don't have one (yet), but it looks like a great thing for the toolbox if you're into that level of poking and prodding.