I want to amplify PWM audio I'm outputting from a microcontroller. I want to play it on an 8ohm 0.5W speaker. Can someone recommend how I should do this?

I think something like a class D amp output stage chip is what I need, but I can't find one that meets my requirements. I need it to run at 5V. Does anyone know of one that will work for me?

I tried making a push pull circuit out of 2N7000s but it was still quiet. Would I have better luck with different transistors?

 

Show a schematic, and we might be of more help.

Pulse Width Modulation

It sounds like you need a different driver, something more push pull-ish.

 

You might just use an RC low-pass filter to change the PWM to a pseudo-sine wave, and just use an inexpensive LM386 audio amplifier.