My advice to you is save up as much as you can just in case you have no one on the outside to provide for you. That's what I'm doing. I know I'm only 20 but I'm definitely not about to have my mom come outta pocket for ANYTHING.
So yeah that's my advice for you. I know 50-100 dollars seems like a joke but you're most likely going to have to dig deep and find a pro that out weighs it.
you can do USNA without your parents coming out of pocket. i had a sort of mutual understanding with my parents that after i graduated high school, the faucet was turned off - period. that was the largest factor in me going USNA over some other school/scholarship.
i graduated in 07 and was pulling in about $550/mo by my firstie year, if i remember correctly. also of note in the finance area is the option of taking out a loan during your jr year, for little interest (mine was 30k at 0.75%). you don't start accruing interest and you don't have to pay anything back until 3 mos after you graduate, so it doesn't come out of your meager academy pay. it's called a career starter loan because it helps you prepare for your career in the navy by going to mexico for 2 spring breaks... i think.