I assume you are allowed to have a job... I wasn't allowed to have a job all through high school. Will your parents give you an allowance if you start doing more chores around the house? The neighborhood odd job idea sounds like a good one. What about babysitting? If all else fails, could you get your parents to combine your birthday and Christmas gifts into one big gift? I got a trip to Florida paid for that way, then a trip to California a few years later. BTW
if this helps, Petsmart sells 75 gallon tanks with light and hood for $189.99 USD.
Billsgate beat me to it about the gift combination idea.