"Arts" festivals can be pricy but they will draw out the big buyers.
The
Paradise City shows come to mind, the county fairs (season's over now) would be another good choice if you have the product for a high end show. They'll get upwards of 1500 for a 10X10 space. The best shows, be they "Arts" of "crafts fairs" will be juried. Meaning you'll need to submit photo's to a comittie who will deceide if your items are approiate for their show.
If the show isn't juried don't waste your time it'll be nothing more than a glorified flea market. STAY AWAY FROM THE FLEA MARKETS ! I'd suggest getting your feet wet at the local craft fairs. You might want to hit a bunch to get a feel for the market - and how to price your product. I did the craft & home show circuit for a couple years selling the rustic furniture you can see in the album on my profile.
Local shows are much less expensive and can range from 20 -30 bucks and up, most are outdoors so you'll want a pop up canopy. Keep in mind these shows do much less advertising and tend to draw the .. more thrifty types.
Once you start doing shows you'll get folks coming through selling "craft fair guides" to the vendors - don't bother with them ! You can find out more using Google. There's also a number of on line resources reveuing various shows. Once you start doing shows talk with other vendors, most are willing to share information on different venues. As long as you're not selling the same thing they are.
Resist the urge to buy anything and pack your own lunch when you're at a show too.
Best wishes and good luck !