Attending a big con can be an expensive ordeal, but it doesn't have to be. There are an assortment of ways that you can make the trip a bit more affordable, but sometimes saving a buck or two isn't worth the effort.
I'll share a couple of generic thoughts that might help:
1) Group up. There are several ways that travelling with a group can be more efficient. A group can extend the comfortable driving distance. Origins is within a (long) day's drive of a good percentage of the US population. Sure, it may be a 12 drive from your town, but if you get three friends to share a car that is only 3 hours driving a piece. Splitting a hotel room is always an option too.
2) Check alternate transportation. For most this means looking at a train or a bus, but sometimes just mixing things up can provide a big savings. One year, instead of flying all the way there, I was able to fly about halfway there and rent a car for a one-way drive to the con. This let me visit with family on the way there and back and the difference in plane tickets because I took a different route made up the difference in having to rent a car and pay for gas.
3) Think about different food options. When attending a con, hitting the food court or going to a restaurant for every meal is a bit much. Columbus has a popular market close to the convention center. Several area hotels also provide lunch and at least one will actually go grocery shopping for you and just charge you the cost of the food. Save time and money by making a quick dinner in your hotel.
4) Ask around. Every year I learn more options because of what other folks have experienced. Origins traditionally fell around my birthday so a couple of free or reduced-cost meals were available for the asking from area restaurants. One place I didn't even know about until a couple years ago and now I would never miss a chance to eat there. If you are staying at an area hotel, ask if they have a concierge. Those guys usually have an "in" at several places and can give great tips that broaden your experience and save you money.
5) Have a backup plan. When I attend a con I keep some OTC medicine, snack food, and water flavoring with me. If I get a headache or cannot get something reasonable to eat I have something to fall back on to tide me over. Nothing sucks more than having to shell out $5 for a few pills or $2 for a small drink because you think the convention water dispenser is unpalatable. A small water bottle goes a long way.
While I'm thinking about it, I tend to find the water in new cities a bit "off" and I'm not keen on spending $4 for that small bottle of "convenient" water they dangle in front of you in the hotels. Before you go to bed fill up you water bottle and the ice bucket with ice. The water used for the ice machine is usually super-filtered because it is cheaper to filter the water than it is to provide extra maintenance to the machines. This means the melted icewater tastes a lot better than what you'll find out of the tap or the fountains.