If you will use a circular saw only for occasional light duty work, get a less expensive model. There are a lot out there and the smaller ones work okay. There are also many heavier units, like the worm drive shown below, which are intended for pro carpenters who will use them long and hard.
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Bosch 1658B-01 7-1/4" Circular Saw
Milwaukee 6378 8-1/4" 15 Amp Wormdrive Saw
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See Amazon.com's larger selection of circular saws by clicking here.