Auto Supply Store? Yes you absolutely can. Walmart, Ace Hardware, Harbor Freight. You shouldn't need to spend more than about $10 for one and Harbor Freight has them on sale for $5.99. Or free with any purchase right now. At least with a coupon. They look like this
They're called DVOM which stands for Digital Volt Ohm Meter. Measures voltage in AC and DC circuits plus resistance of components. If you have a switch in your hand that you want to test, you use the DVOM in Resistance and you can watch the digits change as you turn that switch on and off. ON will display as a very low reading, close to Zero, and Off will look like you turned the meter on and haven't connect the it to anything yet.
