What should i do for my 16th birthday party?

I'm turning sixteen soon, and i need ideas for a party. I live in Australia so yeah just like to throw that in there. and i might be sharing it with my best friend in my year who is turning 14. this means it can be bigger and better. we have a budget of about $300 - $400 i think. we had an idea of a beach party cos my friend lives right on the beach, or a dance party. if i share it with her there won't be alcohol involved. around that time of the year it will be good weather, midly hot. would really appreciate your ideas. and also were concerned about the fairness of the presents - like we dont want to be jealous if one of us gets a better present but we dont want to get the same. we were thinking of having just like a money thing then sharing it equally but i dont know. what do you guys suggest? need party ideas. xxxx