Do you have a Decathlon near you OP? They do really cost-effective sportswear. All you really need to start is a pair of trainers and a decent sports bra. You can manage in leggings and a cotton t-shirt but if you can afford one of the technical t-shirts that would be good as they are more comfortable.
In terms of actually running, most people use the couch to 5k app. But you can also take yourself out and do lamp-posts. Walk to a lamp-post, jog to the next one, walk to the next one, jog to the next one and so on. Do that for about 10 minutes on the first day. Then do it for 12. Then 15, then 18, until you can do it for about 35. And you can change the pattern, eg do 2 lamp-posts runnng and one walking, or 4 lamp-posts runnng and two walking - that sort of thing. Then you can do a parkrun. It really is that easy.
(if you don't have lamp-posts, use trees, or do it by time, eg 30 seconds on and 30 seconds off, or 5 minute ons and two minutes off that sort of thing).
I didn't use couch to 5k when I started running, I could "shuffle" about 15 minutes so I did that three times a week and added 5 minutes to one run a week until I was running for an hour. I then ran my first 10k and then joined a running club. I now do parkrun every week and the odd race.
If you do get into it, it is well worth doing strength and conditioning work too. If you can find an outdoor fitness class near you they are great for strength work and a bit of cardio which will help your running. Or follow videos online.
And you don't need to take water with you unless you plan to do a half marathon the first time you go out, or it's 40 degrees.