A table saw is a pretty expensive tool. You can buy a circular saw for between $30 and $100, depending on the brand.
DO NOT attempt to use a power saw of any type without some training first. An easy mistake like forgetting to lock the plate can cause you to cut off a finger, cut through your sawhorse, cut into your garage floor, or any of a number of disasters.
The home improvement store will often make one or two cuts in the sheet of plywood free, and charge you a small fee (maybe a dollar?) for additional cuts. Girls/Women, though, can often get more cuts for a smile.
With a little training, and proper safety precautions, most semi-beginners can use a circular saw. BUT, please, have someone help you the first time!
Female, and new to power tools myself. I'm using my circular saw regularly, but had an experienced friend show me how, supervise my first attempts, and offer advice and watch-outs.