Home soil tests are usually qualitative and test for only pH, phosphorous, potassium, and nitrogen. The latter is worthless and the former is probably the only one that will be remotely useful. Soil labs will typically give you more quantitative results and recommendations. In addition, they may give you values for micronutrients, acidity, base saturation, organic matter content, and possibly texture. Your state may even test for free through the cooperative extension.

The home soil test kits are quite limited in what they tell you about the soil being tested. The pH test may give you a ball park number but it will not tell you why the pH is where it is or what to use to make any necessary corrections. How much Calcium (Ca) is in the soil? How much Magnesium(Mg) is in the soil? What is the ratio of Ca to Mg?
Available Nitrogen (N) is dependent on soil temperature, so a test in March or April might show a deficiency which might lead to a excess of N being added to the soil. Phosphorus and Potash might show as low, high, or okay but may not be what is reality.
A soil test done by a good soil testing lab will come with recommendations for any needed corrective action and, if you specify, those can be in organic terms, and if the test is done by your state university (in the United States) you can ask your county horticulturist questions about it, something that home test kit does not provide for.

If funds are limited it would be better to test your most important sample now (garden soil?) and do others as funds permit. You could also test a portion of the same sample with your test kit prior to submitting it to the lab and compare the results.

My local University soils lab does all the testing for Extension and they also will test compost samples. If you take your soil in you might ask them about that.

A big waste of your money is guaranteed if you take your sample(s) improperly and handle them improperly after taking them. Consult the chosen lab and/or extension service for guidelines on how to do both before you sample or you may well get garbage in, garbage out.

Check with your local ag center and those in surrounding counties. We have a county about 40 miles from us that has a free soil testing a few months a year. It's $7.00 a test in Florida.

Many of the state universities Cooperative Extension Service offices do take in soil samples for testing by that state university and many have a fairly small fee attached to that testing while a few others have the cost covered in other ways so the test is free to the consumer. How ever AgCanada does not do soil tests so harry57 will have to find a soil testing lab.