In addition to the basic stuff like screwdrivers and socket wrenches, here are a few items that every weekend mechanic should have in their garage:

Shop Light — Shed some light on your work with a good quality shop light. Be sure to pay a little bit extra cash for the stand-up version. You’ll be glad you did.

Torque Wrench – If you change your tires frequently, this is a must-have. Not only does it help you apply the correct amount of torque, it also serves as a nice breaker bar for those stubborn bolts.
Car Ramps - There are two kinds of weekend mechanics….those that prefer ramps and those that prefer jack stands. Personally, I prefer ramps for two reasons…1) the car feels more secure when it’s up on ramps compared to jack stands and 2) it’s a lot quicker to drive up a set of ramps than it is to jack the car up and put jack stands underneath.
Oil Filter Wrench – If you’ve ever tried to remove a slick oild filter with your hands, you know exactly why this tool is on our list of Top 10 Tools. Eliminate ten minutes of frustration by picking up an oil filter wrench for $5-$10.
Code Reader – It won’t solve your problem, but it will point you in the right direction. If you don’t own one, stop by your local auto parts store. Many of the big retail chains (AutoZone, Schucks, Checker, etc) will let you borrow one for no cost.
Gloves – Working on your car means that your hands are going to get dirty. It’s just a fact. Pick up a box of rubber gloves and keep your fingernails dirt-free.
Tire Pressure Gauge — Quick and easy way to tell if your tire is running a bit low.
Magnetic Pick Up Tool — Perhaps the greatest invention of all time, use this handy-dandy tool to retrieve that pesky screw that you dropped in the engine bay.

Multimeter – Without one of these suckers, it’s pretty much impossible to track down electrical issues. And don’t worry about replacing them because they last forever and the technology doesn’t change over time.

Plastic Zip Ties — These little guys are the automotive equivalent to duct tape. Definitely not a long term solution for any kind of major automotive work, but they sure come in handy for quick fixes. I’ve used these more times than I care to admit!