"Why do you think you'll need one? If you're worried about pH, for example brewing with lots of roasted grains, save your money and buy some pH strips designed for brewing."
Sorry man. pH strips are about as accurate as a rifle with a shot out barrel. The brewer probably isn't worried about what lots of roasted grains do. The brewer may be thinking about souring up the mash with lactic or sauer malz. He may be thinking about not stripping tannins during sparge. The brewer may do decoctions, where accurate measurement of mash pH is essential, due to boiling the mash. He may use it for accurately determining water pH before adding chemicals. The brewer may not be interested in saving money by using a tube of 5 dollar, archaic, pH strips. Perhaps, the brewer is focused on owning modern, accurate devices, that aid him/her in accomplishing brewing procedures that create finer, more consistant beer.
OP: I own a Weiss 6250. It's rugged, waterproof, and extremely accurate. However, it's a few bucks more than 100. Weiss makes pretty good stuff. They've been around a long time. The 80-100 dollar meters don't seem to have the longevity when used hard. If you do a lot of brewing and are going to brew for years, you'll go through enough of them to warrant the finer Weiss.