When I changed my grip, I made much straighter cuts without a saw guide. Pro tip: For straighter cuts when not using a guide, ...

the Ryobi 18V ONE+ R18CSP-0 Circular Saw is perfect for making long straight cuts, trimming sheet wood to size, cutting kitchen work tops, flooring or to make quick and accurate cross cuts in timber.

Plenty of sub-$10 ones are available that require you to apply manual pressure to push out the ... like cutting new wood for built-in shelves. Ryobi makes a cordless 18V One+ 6 ½-inch Circular Saw ...