I agree with Funky. When I started running last year because I was a bit of a fatty, I bought some fairly basic trainers in the sale to replace a knackered old pair and they were fine.
Although I have now bought a slightly better pair because those ones got knackered and I’m doing more distance etc.
My only real bit of advice is to try on as many pairs as possible to make sure they fit well. I’ve got quite skinny feet so struggled with quite a few brands. In the end Asics fitted the best, so I bought a pair.
Good luck. You may find that you actually enjoy it. I used to hate running, but gradually I’ve begun to really like it…it’s free, easy to do and you don’t need to do too much to feel like you’ve had some exercise. I’m running the Silverstone half today and am excited about it