I've never been one to buy cheap tools, buying a cheap caliper makes no sense, although there are really expensive calipers available, I think you get more reliability with just a little more money spent. I have a Lyman dial caliper that I paid $40 for 20yrs ago, it is no longer accurate, so they do wear out. I now use a digital that I paid $50 for at Sinclair Intl, it's as accurate as Mitutoyo and Starrets costing 3-4 times as much by their testing as they sell those too.
Charlie, I think you should spend just a bit more money so you don't end up buying the cheap set twice, the first time, then again when you replace it with a good one!!

Tim