Cheap Organic Soil Test for N P K & pH Levels

What I've been using to test my organic soil mixes to ensure that they are ready to be used since both the super soil mix and the organic potting soil mix both need to sti around for a little bit of time so that the microbes can break down all the solid nutrients. This soil testing kit is able to check the Nitrogen, Phosphorus, and Potassium levels that are currently bio-available to the soil as well as being able to check the pH of the soil, all for around $2 per test.

Soil Test Kit: https://amzn.to/3uWS6MS

Previous 4 Part Series on Building a Soil Series:

Part 1: Building an Inert Potting Mix - https://www.youtube.com/watch?v=IwgCDseE7wg

Part 2: Building an Organic Seed Starting Mix - https://www.youtube.com/watch?v=AZO51iLrAP0

Part 3: Building an Organic Potting Soil - https://www.youtube.com/watch?v=AX3p5Qi8Af4

Part 4: Building an Organic Super Soil - https://www.youtube.com/watch?v=SeUZsH6hu4g

Bonus: Soil Amendments - https://www.youtube.com/watch?v=pQZHm1F2gMc