I think gyms have a place and are great for some people, me not so much. I do however believe in weight training and I have a set of free weights but many people use their body weight to train with. This quick video shows you how you can too.
For me the easiest thing has been to find short videos that I can squeeze in 4-5 times a week. Don’t worry if you can’t work-out that often; just do what you can as often as you can. Every workout makes you a little bit fitter than you were before you started it.