These are all great and immediate money-saving suggestions, but I'm going to give you something a little "bigger picture" to think about.
Do whatever you need to do now, to help you get a scholarship to college.
I will be much more apt to have my own children making good grades rather than getting part-time jobs in high school because an education is the number one thing that is going to be economically sustainable for the future.
Another thing to work on now, is budgeting your money. Financial awareness and money management is one of the number one things leading most young people into severe debt.
There are also the little things you can do that add up...like turning off lights when you leave a room, or not turning the air conditioning or the heat up too high. You can also turn off the water while you're brushing your teeth, and not leave leftovers out on the counter to get stale...but cover them and use them for a quick pick-up meal later.
Most high school students have cell phones, but you should research how much your current plan costs and look at ways to cut those costs. Do you really need "unlimited" texting? Look at how many you actually send/receive, and look at your provider's plans to see if you could make a change there. If you have a smart phone, do the same with data plans -- maybe you only need 200 megabytes of data a month rather than an a more expensive plan. Compare various providers for their family plans -- sometimes you can get a significant savings if everyones plans are tied together.
How about agreeing to shop at consignment and second-hand shops than demanding name-brand clothing at outrageous prices? Also, if you are a reader, you could check out books from the library as opposed to purchasing all your own books. Video game players could sign up for a game-exchange (like Netflix for movies) where you play the games you really want to play without having to buy them...they are way too high-priced!
One thing I'm trying to teach my children is to save for the things you want instead of begging me to buy them using credit cards. Cash purchases save money as there are no service fees or interest charged. There is also no risk of fees for returned checks if you pay with cash. This is the best way to live within your means...if you don't have the cash, you don't really need the item you "want".
What a great question to ask! If you can find ways to do small jobs or if you are older, get a part-time job in order to earn money and pay some of your own expenses from an early age, it will be much easier for you when you go to college or move out on your own, as you will already be more responsible with money.
If the family has fallen on hard times (like so many have), then you can share clothes with the siblings, tell your parents you don't want Christmas presents (very hard to do, I know, but is also a gift in itself, to them), concentrating instead on a big dinner at home. Lastly, you can find ways to entertain yourself at home without video games or going to the movies, because many of those ways are free. Good for you for asking.
It's great that some students take their parents' finances into consideration--too many children mistake the words "want" and "need." There's a big difference there, but most children don't see it. The purchase of fashionable clothes and shoes can be tempered; fancy electronic gadgetry can be shared or held to a minimum; and budgets--both for parents and students--can be created and strictly enforced. Part-time jobs for older students should also be considered.
The previous posts have many good ideas. The one that I would add would be to ask your parents to give you a set amount of money each week or month. That would help you and your parents.
If your parents gave you a set amount for your own use, they would know how much you were going to cost them each week or month. That way, you wouldn't be coming to them asking them to buy you this or that all the time. You and your parents could set an amount that would be affordable both to you and to them. If you did this, you would probably end up spending less because you'd be more aware of how much you were spending.
Lots of great thoughts there from stolperia. I have a few things to add. One is to carry your own refillable water bottle. Also planning snacks ahead of time can save a lot over picking them up along the way or hitting a vending machine. If you find a little work, like babysitting, raking yards, or tutoring, set that money aside and don't blow through it right away -make a budget for yourself.
My biggest suggestion, though, is one that will be a great life lesson - understanding the difference between a need and a want. There really aren't that many needs; most things, when scrutinized carefully, fall into the want category. When you have a want, there are several questions you should ask yourself: Why do I want it? Do I really want this particular item, or am I using it to try to fulfill some other need? (Example: wanting expensive brands of clothing because you really want acceptance to a certain clique.) Can this item really do what I want it to do? (An excellent question for expensive beauty products.) Can I put off this want for a little while? (Amazing how many wants die of neglect after a couple of days!) Do I want it badly enough to save and/or budget for it?
My interpretation of your question is that you are looking for ways that you can become less of an expense to your parents. While parents shouldn't ever look at their children as money pits, there are families that would greatly appreciate kids helping to support themselves and reducing the pressure on the overall family budget. As a tenth grader, you are old enough to be able to do a number of different things that can help.
Telling you to find a job is easy to say but may be hard to do in the current economy, so keep that in mind but also look for other ways to help. If you can get by with the same clothes, shoes, book bag, etc. that you used last year, that is a major savings. If you must get new-to-you things, use Goodwill or consignment stores to find used items that will cost much less. Think about the cost of feeding a tenth grader - if you cut down on expensive snacks and fast food in favor of healthier, less expensive homemade items you'll be helping their budget and your health. Obviously, this is not the time to ask for new furniture for your bedroom or other big ticket purchases. You could try finding more free or low-cost activities to share with your friends instead of asking for money to go to movies, the mall, or wherever you might have gone to spend time and money in the past.
Your folks may not say so, but they will appreciate your consideration!