The ones i've got, that were very expensive, i got over the internet. You don't get many strips for your money.
You spit in a spoon and put end of strip with two coloured bands into it for 5 seconds, and that's it. 15 seconds for urine, which you collect in a cup.
Then you compare the colours against a chart.
I did saliva test this morning before eating. It said only slight dietary changes required. I need to do it several times a day to get an average.
I'll let you know if i find a supplier of inexpensive strips.
What i want to know is, how does a slight imbalance affect your health.