When do I need a permit to sell a craft?

You do not need a "permit" to sell your crafts in Ohio, but you do need a Vendor's License in order to collect sales tax.  Anyone can sell things to their friends, family, on the internet, or to anyone, without forming an official corporation or a limited liability company with the State of Ohio.  Your business would be conducted under your own name.  But businesses must collect sales tax from their customers, and in addition, you must report the income from your business and deduct your business expenses on your personal income tax return on Schedule C for business income. You may obtain a Vendor's License from your county auditor's office.  Many counties in Ohio have online applications -- or you can go the the county auditor's office and ask for an application. I am an attorney licensed to practice law in the State of Ohio.  This answer is intended to give general information and not to give specific legal advice.  No attorney-client relationship is established by your asking and by my answering your question.