low budget option
I bought an Oakton pH Testr1. It is not temperature compensated, but it can be corrected with a little table to figure what the reading is equal to at 20C. There is always a thermometer handy, and I live with the single point option, though temp compensation would be handy.
It cost about $150 CAN two years ago. The down side is that it seems to consume power even when it is alleged to be turned off, so I now store it with the batteries off. It is watertight so if you drop it into the rinse water,etc, it is still ticking afterward.
I store it with the element soaking in small beaker of 3N solution of Potassium Chloride. 3N is 3M into 1L of distilled water. The MW of KCl is 74, so 74g into 1L. I actually mix it 100mL at a time.
It is a single point compensated unit; you feed it pH 4, 7 or 10 buffer solution and after it has been stewing for 30 seconds/blinks, you press confirm, and adjusts the display to be either 4.0, 7.0, or 10.0. Fancier units get fed two buffers, and set the zero offset and slope from these two measurements. The buffers are commercially available where the units are sold for about $5 per bottle, and the bottles go a long way; I pour a small amount, say 10mL into a childs medicine cup and calibrate on this amount.
I bought it at a local hydroponic shop - ie storefront for the average dope grow-op guys. I bought it on a credit card, and they were tickled, because they had only recently got the credit card terminal, and I was the first customer to ask to use it. It seems that most of thier customers like to deal strickly in cash.
