As a veteran of many craft fairs, let me say the only people making any money will be the ones selling the soup and sandwiches. Sometimes I think that's the only reason they want the vendors there.
You will get a lot of oohing and aahing and oh how pretty and my haven't you been busy until your head will explode.
Most of the folks who go are looking for ideas they can do.
Sorry if I sound cynical, this is why I stopped doing them.