How much is the stand costing? I am sure it would be worthwhile. Take plenty of business cards along as well as your portfolio and perhaps a model or two to do demos on. Good luck and let us know how it goes.
Definitely a good idea. What bride doesn't want to have beautiful hands & nails for their wedding day when showing off their wedding ring? (& she won't want hubby to have scuzzy nails either). Your 'audience' will be in a romantic mood & prepared to part with money as weddings aren't cheap. By showing them at the fair how good you are you'll be saving them the leg work of trudging round the salons. Plus for those brides who hadn't thought of having their nails done (are they mad?), you might give them the idea. You should also hook up with all your local wedding shops so you'll be everywhere & everyone will think you're THE person to do their nails because you're everywhere.