to be honest, if funds are that tight, I'd scale back. Because craft shows are a gamble and if you are on food stamps then I'd not want to risk what money I have. I've spent hundreds of dollars on a show (back when I was new) and lost money. Now, I know what shows and I make a lot, but I've been doing them a long time AND I have a product that is used up and needs to be purchased again.
I'd do the low/no cost things. And to give away your items for a fundraiser is very kind, but again, something I'd only consider doing out of my excess.
Just a suggestion.