If you're really just starting out, I'd suggest any kind of supply for several fixed voltages (3.3, 5, 9, 12, 24, whatever), maybe an ATX supply with the output enable strapped on. Then when you need an adjustable voltage, reduce it with resistors, or use an emitter follower or LM317 circuit, or any number of other approaches. Later on, you can get a proper adjustable supply when you've outgrown your use of this method.
Tim