The most important piece of kit will be your running shoes, which should be comfortable and suited to your running style.
At this time of year thin layers are best, so a long sleeved wicking top for those cooler days, a running vest or short sleeved wicking top for warm days. shorts or thin trackers complete the kit apart from socks.
Good luck and you don't need to spend a fortune, look around for bargains and last years stock on sale.