Ok, lets see here. I guess I would start with a question......If you are growing in soil , , why do you feel you need a pH meter?
Bottom line is that soil self adjusts pH to plant needs! This of course would be somewhat contingent upon you using a QUALITY soil premix or that you are mixing your own "Subs Super soil" style mix. Even growing with a QUALITY synthetic (Most QUALITY synthetics for soil are pH neutral) the need to pH adjust is rare at best!
If your organic then there REALLY is no need to pH your soil !!!!
With that said then I'll go on to this....A pH pen for liquids is not going to do that much for you is it? You see what would matter here is the pH of the soil......So , , if you REALLY still want a pH meter. You should look to one for soil! Do yourself a favor and DON'T spend your hard earned dollars on a cheap pH probe from a gardening store (rather inaccurate)!
I should add this fact here: 99% of all hand held pH, TDS/PPM, EC and temp meters are built for the hobby/greenhouse growers and they are made to be affordable and functional and should never be considered as "LAB QUALITY EQUIPMENT"...They do work just fine for those things and will fit most everyone's needs!!!
Now then. Some manufacturers of Lab quality equipment do make these "inexpensive" Hobbyist grade meters. They are HANNA, OAKTON, and for the most part, BLUELAB....Now then the one you have found on Ebay is listed at $150. Thats ok but it's not for soil!
I would say try this one from HANNA as it does everything the other does AND more for only a little more and is more of a "pro" model that packs lots of feature's into a unit that covers all types of growing media.
http://www.labdepotinc.com/Product_Details~id~385~pid~6284.aspx
IF you only want one for soil applications that is easy to use and carry , , then look at this one.
http://4hydroponics.com/bluelab-soil-ph-pen
Generally speaking unless your an advanced grower mixing your own nutrients to specific concentrations or chelating your own synthetics. Then I don't see the need for you to have a TDS(PPM) pen or multifunction meter anyway.
Now then to all you NAYSAYERS on soil not needing pH.....The water going in will be x.y pH and coming out it will be y.z and all the while your soil WILL be right about 6.5 give or take a factor of as much as only.2.
If you need to understand how and why soil self pH's then you ALL need to read this (and for sure if you don't believe me)!!!! THIS is the book I would say is a must read for anyone wanting to grow organic....
http://www.amazon.com/Teaming-Microbes-Organic-Gardeners-Revised/dp/1604691131/ref=sr_1_1?ie=UTF8&qid=1377898347&sr=8-1&keywords=Teaming+with+Microbes+The+Organic+Gardener's+Guide+to+the+Soil+Food+Web.
So, now I have given knowledge and that is the key for anyone to make their OWN decision!
P.S. Milwaukee meters are fine. In fact I have a pocket pH meter from them for "on the fly" readings at work....Those readings are then qualified with a HANNA HI2215-01 LABORATORY meter.
I hope this helps you and others to make a sane choice.