It's prefect for fourth of July and it will sell out really soon since there are only three left, but its 30.00 and our family is really low on money and I don't have any at the moment, nor do I have time to make the money before it sells out.
Im sorry to say this as I'm sure you really want it, but if you can't afford it don't buy it or pressure your parents to. What you can do if its that important is ask a really close friend to lay out the money. When you get a job you can pay them back
If you've not got the money, then you can't afford to buy such luxuries and that's the reality of it.
I'm sure especially as your family haven't got that much money in at the moment, you wouldn't pressurise them simply for something that you have no need for. Earn some cash and get a dress nearer the time, don't be selfish.