Best running outfit

Hello! I am training for a marathon on December 8th and currently have a $100 gift card. I am trying to purchase an outfit that will be suitable to run 26.2 miles in!!

I am more so looking for shorts and some sort of exercise bra/athletic top. I am around a size 8. Please note that I do have slightly thicker thighs that WILL chafe so I am looking for something that will prevent this.

Any advice or recommendations are helpful! Thank you!