The pH / moisture / light meter that I bought was about $25, and can be used as often as I want, in all areas of the garden. It's not left out, testing takes about a minute or two and then the meter's put back away.
The soil test kit that I bought was about $3, but could only be used once... and I've never used it.
I figured that if I wanted to test multiple areas of my garden, throughout the year, the meter would pay for itself. We've already used it at least twice, once for each blueberry bush, just before I used the organic soil acidifier the first time. We'll use it again on the two beds about 60 days from that treatment, to see if I need to add the soil acidifier again.
By the time I've used the meter eight or nine times, it'll have paid for itself.
Now, I certainly would agree that getting a soil analysis/test done when beginning a gardening project is worthwhile. And it should probably be done periodically, maybe every 1-3 years? But I haven't done that.
I don't think anybody wants to be paying the extension office to test their soil every week while they monitor changing pH levels.