Pond Boss Forums GENERAL QUESTIONS Water chemistry Water testing kit

I've never tested the water in the pond, so it looks like it's time to start.
Without spending a whole bunch of $$, what's the opinion on:
LaMotte Dissolved Oxygen Test Kit combined with Laguna Master Pond Test Kit? If I get those two kits, am I missing something?
Are there test kits that are more cost effective?

Where should the sample of water be taken from (top, middle or bottom of the water column), or does it matter?

How often should I test?