Do you have any cheap ideas for a party?

My birthday is in like 50 days, and I want to have a party with all my friends, but the thing is I can't spend a lot of money. My mom says that I need to just invite my friends and go see a movie and out to dinner or something like that... but I want to have like 40 people come and chill at my place or something like that.
Do you have any good idea's for a party that would be really cheap?

Why not talk to your closest friends and set up where everyone brings something like drinks, chips, and little things like that and maybe find a place outside or anywhere that is free and just have lots of people come just to hang out. Drinks are cheap(even cheaper if not name brand) and small foods(like chips cookies, and so on) aren’t that bad. That way no one really has to spend a lot of money and every one can just talk and hang out. B-day are about the people you spend them with and the memories you make with them, so most importantly just have fun.