Hardware tool
Getting started with electronics design takes buying some equiptment, but it can be confusing what to buy. I'm going to list here some of the items that I throught were helpful getting started.
Contents
Breadboard with power supply
Most people start with electronics by connecting up circuits on a breadboard. A breadboard is great for trying out circuits before moving to more permanent construction techniques such as perfboard or custom PCBs.
Spools of wire
Wire is available as stranded or solid. Solid works best with boardboards and perfboards. Stranded works best when creating cables for interboard connections.
Multimeter
Radio Shack is a good source of cheap multimeters.
Oscilloscope
An oscilloscope is critical for debugging analog circuits or communication protocols. I prefer PC based oscilloscopes since they are cheaper then dedicated equiptment and are more automated then a traditional phosphor oscilloscope.
See oscilloscope
Storage compartments
As more components are bought, it becomes necessary to store all the components in an organized way and storage compartments are very helpful. These can be bought at the local home improvement or hardware store.
Resistor kit
It's important to have alot of different resistor values around as it's almost impossible to buy the correct values in advance. Digikey sells resistors in kits that have a small number of all the standard resistor values.
Capacitor kit
Capacitors are like resistors. You need a large number of values. Digikey also sells capacitor kits in addition to the resistor kits.
Microcontroller Programmer/ICD
Microcontrollers are a great way to get started in digital electronics. They are essentially a little computer on a single chip. Unlike large computers these processors usually don't run a full blown operating system so dedicated hardware is used for programming an debugging. In Circuit Debugging are the prefered way to go for development since it's a huge time saver to be able to program and debug software without needing to pull the chip from the circuit. Beleve me, spend the extra money it is worth it.
Development Boards
If you are willing to spend some money development boards are a quick way to get started. They typically have a microcontroller, voltage regulator, some LEDs, and some sensors all on one board. The downside is that if you break anything on the board you have to buy a whole new board. With descrete components only the broken part needs to be replaced. On the other hand, more and more components are only available in surface mount packages which almost require a custom PCB to use at all. ARM processors are relatively powerfull microcontroller but at present are not available in through hole versions.