Advice on what module and parts I may need for project.

Projects General Guidance
1

I want to build a small board that I can either load an audio file onto or have a micro sd card on with the audio file. Need it to have a speaker and a power source.

I want this to be really small and have the ability to push button to play the sound.

speaker I've been looking at just so you have an idea of how much speaker I want:
3-inch Speaker Diameter 77mm 8Ohm 8R 3W

Anyway this is not much info but I'm new to this and trying to learn. I will be able to very grateful on any advice I could get. Thanks, Jonathan

2

Most Arduinos are not a good fit for this project. They don't have the processing power to decode MP3s and they are too big physically.

Look into a Teensy 3.2 and the Teensy audio board. That may do what you want.

There may be other solutions out there that don't use an Arduino at all. This seems like the sort of request that will have off-the-shelf products available.