Dear Mister Race Director: Every aspect of your race is either a "cost center" or a "profit center." Aid stations. Cost center, right? Well, maybe. At worst, they might represent a very small cost, or no cost at all. They might, however, even be profit centers, if it's a big race you're putting on.
I like to look at aid stations like parade floats. Imagine all the floats during the Rose Parade running out of gas at once, and the folks watching all got up from their lawn chairs and started walking the parade route. That's the event you're putting on. Mobile spectators, each aid station is a stationary float.
That's how I like to think of this. Mister local businessman: you have 300, or 1300, or 3000, sport-specific consumers rolling by your "booth" at mile-3 of the run, or mile-20 of the bike. If looked at this way, an aid station is a way for a business or organization to display its friendliness, its helpful nature, its cheery employees. Before you crack a sarcastic remark, remember that Wildflower is famous for its mile-4 aid station. The ability of a business to cheaply create a legendary aid station is only limited by its creativity and adventurous nature.
There are two places to go looking for companies or organizations that might want to rise to the challenge and erect and man an aid station: businesses that specialize in selling the sort of thing you see at aid stations (grocery stores, sports specialty stores, vitamin stores); and those that sell other goods and services and just think it might be fun to support a local event and get the word out about what it is they do (banks, hardware stores, restaurants). I like to think businesses local to your event would be your best play here.
Whose job is it to "sell" these aid stations which, in fact, are not usually sold, but are usually given away (you agree to work the aid station for free; we agree not to charge you for the "booth space.") Probably your volunteer coordinator does the job, however, it might be something your expo booth seller offers as a package (we'll give or sell you expo booth space the day before the event, at registration, but it comes with your manning an aid station). In any case, the volunteer coordinator has to be involved, because he or she is in charge of making sure bodies are where they need to be on race day.
Depending on what you offer at your aid stations, a grocery store might be a good in-kind partner. In fact, sidle up to those grocery stores if you can. Realize they can "sponsor" an awful lot of your event needs without having to actually pay very much themselves. Do you need Gatorade, Coke, Powerbars, bananas, oranges, bottled water? They can (and do) hit up their suppliers, who themselves offer co-op or in-kind sponsor dollars on a use-or-lose basis.
As has been discussed in previous articles (links to them are just below this article), this might be the place for a strategic selection of your charity. Ask your local grocery store what charity they're benefiting—I guarantee you they have one. If you make it your event's charity as well, the store may roll out the red carpet for you: they may tap their employees and customers to be your event's volunteers; they may give you ice, pre- and post-race food; aid station supplies. And you might still be able to tap their charity for their bank of volunteers.
This still leaves certain "infrastructure" issues: pop-up tents, tables, chairs, coolers, paper cups, garbage cans, and so forth. This is, again, the elegant thing about a grocery store: minus the tents, tables and chairs, it's got all of this. If it's specialty stores that're helping out with aid stations (bike shops, run stores) they've often got pop-up tents and tables, if they do expos. Otherwise, ask the city where the event is taking place to borrow their tables, chair, tents. You'd be surprised what they'll offer for your use, but if you don't ask, you don't get.
Take aid stations seriously. Do not run out of ice. Or water. Or sponges, or whatever it is you've got at your aid stations. Don't over-aid your folks either. If it's not particularly hot during your event, I don't think you need an aid station for a bike ride that's 25 miles long, or shorter. But, tell your folks there is no aid station on the course if you don't intend to have one. Send them into your local bike shop partner to get water bottle cages, water bottles, Bento boxes, and the nutritionals to stock them.
But whatever you warrant to your customers that you'll do, do it. Don't say there's going to be water and ice and gels at the 3-mile mark of the run, and then run out or fail to provide these items, or this is the only thing your customers are going to be talking about for the next several weeks (probably on my forum board).