It costs a chunk to run, but saves a lot in health bills - even in countries where healthcare is universal. Heart disease is both a killer and something that can incapacitate you, and any potential weight loss benefits aside, running is fantastic for heart health (provided you do it properly and with the approval of your medical professionals). Not to mention it also has focus, mental health, and sleep quality benefits. Plus if you really get into it, you’ll soon be training for some disturbingly long race and be too busy to do much of anything - especially shopping for pointless things you don’t need.
I’d say that most people can get started with decent wicking workout clothes (thrift them if you can and go for gaudy neons if you live in a place that’s dark most of the year), and a pair of decent running shoes on sale. Wireless headphones and a running belt (or just going for pants with zippered pockets to hold your phone) are small upgrades that also make it better if you have a bit of extra budget. Run like this for like a year, and then slowly upgrade with gadgets like running watches, CamelBak backpacks if you start doing long distances and feel like you need it. Also consider investing in slightly better clothing based on what you determine your needs are - colder climate thermals, merino, running shoes for specific pronation, and rolling tools to help you stretch.
Running can be as cheap as less than ~$100 a year or as expensive as you want it to be. It’s cheaper than the gym, CrossFit, at home workout equipment, yoga classes, etc. Not to shit on those things at all, in fact cross training helps you build strength and avoid injury. But nobody should ever feel discouraged by running due to costs, it pays off in spades.
And for new runners, run s l o w. Slower than you want. So slow you feel you’re not doing much and practically walking. Slow and long runs are the ones that make a real difference in building stamina, cardio health, and even decreasing your race times. You’re also less likely to get injured and prematurely get winded by using up all your energy in a sprint. Also, walking is fine. Even experienced runners walk during certain moments - usually for me, I’m doing it to get a burp out or something.
As a warning to anyone reading: don’t start running to lose weight. Running burns calories and can increase your calorie maintenance, but it will also make you very hungry. Weight loss is mainly about CICO, and you can’t really outrun the fork. Since running can be very natural to humans as a form of movement, it also burns very few calories for the effort. I feel like weight training is a more fair calorie spender for the effort.
But running and taking care of myself does make me pick healthier options. Running helps me sleep, so I’m less tired and as a result, less hungry and prone to wanting unhealthy snacks. Fried greasy foods aren’t great fuel for runs, so I’ll naturally pick things like oatmeal, bananas, veggies etc. But be warned, many runners also love a post run beer so YMMV.