Depends on your definition of "good". How accurate your sample represents the ground is the most critical. Not the test itself as that is simple chem test that will tell you what is in the sample.
I sent a sample in to our Cooperative Extension. It was under 20 bucks, I think... I did this when I first made my garden, because I just wasn't sure what the land had previously been used for. Didn't want to kill my family, trying to grow healthy food! If you want something simple just to gauge acidity, etc. for general purposes- the little cheapy kits work okay. I have one I got at a garden show for 11.00.