Yes, in most cases, you do have to charge sales tax at a craft fair. If you are selling physical goods, most states require you to collect sales tax at the point of sale, even at a temporary event like a craft fair.
The rules vary by state. Some states exempt certain items like handmade clothing or food, and a few states have no sales tax at all.
Before your first event, check with your state’s department of revenue to find out what applies to what you sell.
You will also need a seller’s permit in most states before you can legally collect tax.
Keep a record of every sale and the tax you collected. When it comes time to file, you will report and remit that amount to your state. Most craft fair vendors do this quarterly.