I find that volunteering for cons can take much of the financial sting out of it...check with the con's organizers and find out what sort of help they may be looking for. also - if the con is in another state...many of the forums linked with it offer cheap solutions to that issue as well (rides - invariably.) often - you get perks such as free admission...hotel space and eats...sometimes you even get discounts from the vendors too...depends on the con though.