A grant is money that is given in exchange for either information or fulfilling a purpose that is laid out in contract form.
In other words, you will get money that will be spent for a SPECIFIC PURPOSE...and you must document that purpose to the entity that you recieved the grant from.
Keep in mind that a successful grant application (where you are funded and get money) is a contract, which is legally binding. You will be held accountable for everything you write in your proposal. I've seen grant writers who are now serving time in a federal prision for misrepresenting something on a grant application.
Grants are not 'free money'.