The cheapest new meter (with a cal file from our download site) is the RadioShack meter.I would like to keep the price of the mic below $20
To measure above ~3KHz and generally more accurate you would require the Galaxy CM-140.
The best mic and preamp would be the ECM8000 and XENYX802.
You also require an external USB soundcard for most laptops, as they don't have a line-in facility. Mic-in is not suitable.