Formal HELP ME PLEASE

Hey guys I need help to pick out formal high heels and a formal dress. I have blonde hair and blue eyes (Idk if that changed what sorta dress I wear or not but), I'm from Australia and live in a small town so formal for us isn't long to the ground dresses, it's more like play suits or mid length dresses. I have absolutely no clue what to wear I was kinda thinking a play suit with simple high heels, if anyone can find a dec looking dress and heels pls post the pic in the comments with a link to the website where I can buy it. Since I'm only 13 and only have two jobs I average $50 a week and I wouldn't like to spend all my money on a dress so if it could be from $50 at least-$100 at tops that'd be great, thanks guys 👍🏻