Here's my disclaimer: I am not an accountant, a tax preparer, or a lawyer. I cannot be held responsible for any advice here, I am just providing information and hopefully bringing light to legally making a profit in the United States. All information here is my personal opinion.
First of all, I would like to warn you about making internet searches to pay sales Tax. BE SURE THAT YOU ARE ON THE GOVERNMENT WEBSITE! I found that when I searched on the internet, that there were more service trying to help you collect and report sales taxes that are not the government sites. You should not have to pay anyone to turn in sales tax.
Also, you should collect sales taxes and report them. Many crafters post a sign that says the taxes are included in the price of the product. Personally, I think this a great way to take care of the time it takes to add the tax to each item during a craft show. Just be sure when you price your items, that you include enough for you to pay your sales tax and also make a profit.
A side-note about including that in the price, I always wonder if they are really reporting all their sales, but I guess that is each person's conscience. I think you should report any and all sales, to follow the law.
Sales taxes are paid directly to your state, so you will need to consult your state and maybe even county for specific rules on sales taxes collected.
Sort of entangled in the subject of sales tax is reporting your income to the IRS. You should file if you fall under the guidelines that the IRS requires. This is from the IRS website about self-employment and small businesses:
You have to file an income tax return if your net earnings from self-employment were $400 or more. If your net earnings from self-employment were less than $400, you still have to file an income tax return if you meet any other filing requirement listed in the Form 1040 instructions (PDF).If you need more clarification, you can go to the IRS website HERE. If you need further advice, please ask your tax preparer or accountant. Basically, if your Profit/ Loss Sheet says you made more than $400, then you need to file. If you are profiting far more than $400 each year, you should look at also paying quarterly for your Social Security.
Whew! I hope this all helps, but am afraid it's more like mud. Again, I can't reiterate more, that you should consult a professional if you have questions, although checking the IRS Website can also be very helpful and free.
For a complete list of the 31 Day Until A Craft Show series and links to each post go Here to Day 31.