It's kinda like trying to get a motor builder to sponsor your first motor. Not gonna happen to often. You gotta have a winning ride first then you can get some help. I do have a few friends that have gotten sponsor "help" from Lincoln Welders, food gift cards from Applebee's and Golden Corral, gift cards for gas (don't remember who from) and other kind of gift cards.
Not many can afford to (or will) just hand out cash or have it in their budget, but you can get gift cards and use each ones product which will help pay some of your expenses. You've got a better chance of getting a lot of small sponsors than you do at one big sponsor.