High school proms can cost hundreds of dollars for the dress alone, but do not expect to receive a grant to pay for your expenses. However, you might find grants to pay for prom expenses for the entire school, which might lower your overall prom expenses. In general, you must rely on cost-cutting measures or saving money if you cannot afford to go to the prom.
Do not plan on receiving federal or state grant money to pay for a prom. In general, governments do not award money to pay for personal expenses such as a prom. If someone claims they can get you a government grant to pay for your prom, it is probably a scam in which the fraudster tries to swindle you out of money to "apply" for the grant.
The most likely source of prom grants are from foundations that want to help schools pay for events that provide a safe and substance-free environment for students. Zinch.com, for instance, held a competition in 2011 for a $10,000 grant for the school that got the most votes on their website. The Ethan Foundation and United Way of Story County, Iowa, offer grants worth several thousand dollars to help schools pay for post-prom sober parties.
A more likely scenario for paying for a prom is to help your school hold a fundraiser. You could ask students and the community to donate old formal wear and dresses for resale. Involve the parents, such as with a wine tasting. You might go the traditional fundraiser route with a candy or bake sale. If you work at a restaurant, especially a big chain, it might donate money for a prom to a high school organization in which you participate.
Cut as many costs from your budget as possible. Instead of buying a dress from a premium clothes retailer, purchase one from a department store or secondhand shop. Apply your own makeup, paint your own nails and have your parents drive you to prom locations rather than hiring an expensive limousine service. If you want to go "all out" for the prom, get a job well in advance in case grants won't pay for everything.