Buy a LM386, this chip has been around for ever, is cheap, plentiful and the recommended supply voltage is 4-12VDC.
With the notch on the chip facing you and pointing up, the pinout from left to right, top to bottom is:
|Pin 1 : Gain||Pin 8 : Gain|
|Pin 2 : Input –||Pin 7 : Bypass|
|Pin 3 : Input +||Pin 6 – Voltage Supply|
|Pin 4 – Ground||Pin 5 – Voltage Out|
To get some sort of sound going, you’ll need the following:
- 10ohm resistor
- 10kOhm resistor
- 0.05uF capacitor
- 250uF capacitor
All of the above information can be found on the Texas Instruments LM386 datasheet, very handy!