Mike Fleming | Sales Tax and More: “Technically, all sales that cross a state line are a use tax. This is because when states first began to impose sales taxes back in the 1930’s it was commonly believed that states could not directly tax interstate commerce. So, a sales tax could only be imposed if the transaction happened 100% inside the state. To prevent out-of-state companies from having an unfair advantage, the concept of a use tax was introduced. Use tax is for the storage, use, or consumption of a product or service in the state. It is not a tax on the transaction, but on the taxpayers of the state, so it’s not a direct tax on interstate commerce. If the seller had nexus, they were required to collect the use tax. If the seller did not have nexus, then the purchaser is responsible for remitting the tax directly to the state. In 1977, the US Supreme Court said that states could tax interstate commerce directly and some states did away with a seller’s use tax and only have a consumer's use tax at this point. I do not know of any resources, but anywhere you have brick and mortar you generally want to register for the sales tax. If you do not have brick and mortar, then you would generally sign up for use tax if the state still makes a distinction. Don’t accidentally register for the consumer use tax. However, with the advent of economic nexus, some states, like CO, are requiring remote sellers to register for sales tax, and are even requiring the conversion of existing use tax accounts to sales tax accounts. We may see more of this in the future.”