Many large organizations have annual budgets to support their community, and many times all it takes is filling out a form, or asking.
For example, at most WalMart locations you can fill out a form and if they will automatically provide a financial grant if they still have the funds. If their annual budget is already spent, find out the date it is renewed and come back on that date to be first in line.
Try contacting big corporations with local offices, your local government offices, or non-profits with local roots to see if they have offer grants for educational programs.
If you're speaking to someone who handles local grants, but they don't currently have any funds, make sure to ask if they know any referrals who do!