I recommend buying a Disney gift card before entering the festival. They sell small ones on a bracelet. Put however much you want on that you think you will spend at the booths. SO much easier and quicker than having to take your credit card or cash out several times! We do this every year!
I do this every year and highly recommend. The wearable disney gift cards can be purchased at the Festival Gift Shop - its the large wooden kiosk across the walkway when you cross from Future World into the World Showcase. I use it as a "baby budget" by loading a certain amount of money on it and then trying to keep within that amount. If you don't spend everything on your card at F&W, it can also be used in any gift shop in WDW.
Remember if you are on the Dining Plan to use your snack credits for the most $ items at the F&W kiosks. Then use your gift card for the less $ items and for wine/beer. There will be a purple and white symbol next to those items that are eligible for snack credits. Only food items & non-alcoholic beverages are eligible for snack credits (no booze).
Definitely check out online resources before you go to see pics of some of the returning favs eg disney food blog has some good coverage with photo links. Some perennial favourites on the boards are Australia (lamb chop), Mexico (shrimp tacos), Hops & Barley (lobster anything), France (escargot, creme brulee), Ireland (fisherman's pie), Scotland (scallops) and Canada (filet mignon & cheddar cheese soup . . . mini versions of what is sold in signature Le Cellier restaurant). Some like to try the kimchi dog at the South Korea kiosk. While not strictly part of the F&W Festival, the cronut at the Refreshment Port is definitely worth a try as is the School Bread and Lefse at Kringla Og Kafe Bakeri. The Werther's Caramel Shop in Germany is also a must do. No doubt I have forgotten other besties and other posters will remind me of them

ABC's The Chew tv show also has 2 special booths that are brand new this year: Sustainable Chew and the Chew Lab. Also watch for the DIS Unplugged online coverage. Last year, they had a show with a lot of time devoted to the F&W offerings and I expect something similar may happen in the next few weeks. While you are waiting, perhaps check the DIS Unplugged archives for last year's F&W Festival show.
If this is your first time at F&W, I wouldn't rush to purchase a bunch of $ add-on packages or events. The kiosks alone in the World Showcase are incredible and if that is your only actual F&W thing, then you are in great company and will enjoy!