The state of Illinois requires all businesses, even home businesses, to register with the Illinois Department of Revenue before selling goods. A seller's permit is required if you plan to sell or lease property or services that would be subject to tax at any other retail outlet. You must be aware of the state sales tax -- 6.25 percent, as of 2010 -- as well as the local sales taxes of your county and city. Register your business in Illinois so you can properly pay the state and local taxes.
Register your business with the state of Illinois. Before you can apply for a resale -- or seller's -- permit, you will need to make sure the state knows about your business and what you intend to do. According to the State of Illinois Business Portal, registration requirements are handled by several state agencies and offices, depending on the type of company you're registering (for example, limited liability corporation, limited partnership).
Contact the Illinois Department of Revenue (DOR). Businesses, especially resale businesses, in the state of Illinois are required to be registered or licensed by the Illinois DOR.
Complete the proper tax forms. To be allowed to sell goods in Illinois, you may need to complete the REG-1, the Illinois Business Registration; the IL-W-4, the withholding allowance certificate; and the CBS-1, a notice of sales or purchase of business assets. Make sure to contact the Illinois DOR to make sure you complete the proper forms.
The state of Illinois imposes a retailers' occupation tax on the gross receipts of any business.