I second the quality issues Jason outlines here. I depend on good pH meters to help make my living and good ones simply are not cheap. Cheap ones are basically worthless in a very short time. I've tried most and this has proven true over and over again.
That said there is a pH pen made by a company I use upper end meters from and I want to try one. They are getting good reviews so far from a couple of folks I trust. If they keep proving out, I will try and possibly splurge on one myself. These run about 150.00.
Just restating what I mentioned above.
I'm sorry, and do not mean to sound rude, but I would not suggest the Oakton pH meters at all. I have never seen one of those remain reliable for more than a month. Honestly, I have never seen any meter at that price point have any longevity, and by that I mean more than a few months, even when cared for meticulously.
With any pH meter, care, storage, and calibration are essential for dependable results. You must have fresh calibration buffers/storage solutions on hand at all times, because without them, a meter becomes useless in a short time. Also, pH sensors do have to be replaced every so often as well, no matter how good they are. Depending on what they are exposed too, this can be as often as a year or less. I would think most Pool Owners would get a couple of years out of a good sensor, if they cared for it extremely well.
Repeating, MyronL arguably makes the best handheld pH instruments you can buy, and I rely on one every single day for systems requiring critical pH parameters with very tight ranges. Of the many I have tried, they have proven time and again to be the most reliable and long lasting. Even these have quirks at times, but are usually easy to overcome. The unit I carry is vastly too expensive for any average pool owner. However, the company has come out with some simple instruments for pH/ORP/TDS etc. and I have heard very good things about them from a couple of people. If I were suggesting an "economical pH meter it would be one of these. I may have to break down and try one out. They run about 150.00, and may well be worth the investment for people having real trouble with the color block/Phenol red test. Based on years of experience with their other products, these would be the most likely I would try in the "cheap" pH measurement category.
http://www.myronlmeters.com/Myron-L-PT2-Ultrapen-Multiparameter-pH-temperature-p/dh-up-pt2-ss.htm