I haven't done any soil testing so far. Every test costs $80. I do sheet mulching (because of the lack of soil) and I really have no clue what is in the soil.
I would rather pay for a decent soil tyest kit, because I need a huge number of samples as every spot is different.
Actually soil testing could be a small business idea - but then I don't know you might have to spend a lot!
For the tests that cost $80 they're usually using lab equipment that's pretty expensive for the layman to pick up just to do their own samples. I myself like Peaceful Valley Farm Supply's Soil Test when I need a detailed soil test. They also sell DIY kits but none of them do more than pH and N-P-K
"Instead of Pay It Forward I prefer Plant It Forward" ~Howard Story / "God has cared for these trees, saved them from drought, disease, avalanches, and a thousand tempests and floods. But he cannot save them from fools." ~John Muir