Sharon,
Technically, the
Epcot International Food & Wine Festival is something that anyone can enjoy at no added charge once they have gained admission into the Epcot theme park. So to say "free", might be a stretch, but you don't pay an added admission to the event in general.
After you have entered the park, there are several different elements. Let's go through some of the highlights;
Food Booths: Of course you pay for whatever items you order, but the booths located throughout the Epcot World Showcase are a great way to dine.
Exhibitions: There are cooking exhibitions and classes throughout the event. Many are at an extra charge, though there are some that are free.
Events: Popular events, like the Party for the Senses, as well as other special parties, tastings, and dining experiences abound. These are typically extra charge events.
Eat to the Beat Concert Series: Not an extra charge, but premium seating to these concerts often comes as a perk to one of the events previously mentioned.
So no, technically there is no extra charge to the event. But there are a large number of events tied to the festival that do come at an added charge. I would recommend you check the link above to learn more about some of these activities.
Have a magical (and delicious) vacation!