Do I, as a resident of Illinois, owe tax on internet purchases?

Maybe. If an internet retailer does not collect tax on their sale to you, an Illinois purchaser, then you must pay use tax directly to the Illinois Department of Revenue. If your annual use tax liability is over $600, use Form ST-44, Illinois Use Tax Return, or if your annual tax liability is $600 or less, pay with your  Form IL-1040, Individual Income Tax Return.

If you have additional inquiries, you may submit them to the Questions, Comments, or Request form.