Running is one of the most convenient and affordable forms of cardio, as you only need appropriate clothing and shoes to get started.
"Finding a safe and convenient place to run is important, especially if you plan to run outdoors," Victoria Nolan, an NASM-certified personal trainer at Suite Time Fitness in Houston, told POPSUGAR. "Ask around on social media for tips on where to run in your area. You will want access to well-lit parking lots and paths, water, and restrooms or changing facilities."
Just be sure to take it slowly when you first start running. It's normal not to be able to run a full mile at the beginning; instead, alternate between a few minutes of running and walking for the first few weeks.