We don't know what state you are working on so we don't know how the question is worded.
In general, you are supposed to pay sales tax (or use tax) in your state for something that you buy to use in your state, even if you buy it out of state. It could even be argued that you should pay use tax in your home state for everything and then get a sales tax refund from the state where you bought the item, but I don't know of any state that actually requires this. What the state does want, is if you bought something tax-free out of state, you should pay use tax in-state. So they have added a line on the income tax form where you can voluntarily pay state sales/use tax for any items you bought tax-free out of state.
So, if you are pretty sure that all your catalog and online sales were taxed, then you can answer that you do not have any tax-free sales to report. If you think you probably did buy some stuff tax-free online, then you can answer yes, you had tax-free sales. In that case, depending on the state, they might charge you a fixed amount based on your income, as a rough guess of what you might owe. Or, some states might allow you to declare the actual amount of your tax-free purchases.
