Contact your state and local tax agencies

The agencies that collect sales taxes also hand out the numbers, so contact your state, county, and city tax agencies to request a registration form or apply for a sales tax number online.

I recommend: Look over the sales tax requirements for your state to make sure you're collecting everything you need to. The IRS also has links to state taxation authorities.

Get help for managing your sales tax compliance

Web-based services are available.

I recommend: Alavara has helpful services to manage sales tax compliance.

Consider where you do business

If you sell taxable goods to customers outside your state, you must decide whether to collect sales tax on those sales. In most cases, you're not required to collect such tax; instead the onus is on the buyer to pay an appropriate use tax while filing his annual state income tax. However, if you have "nexus" within a state — that is, a physical presence such as a warehouse — then you may be legally required to collect sales tax, although court rulings on this matter have been inconsistent.

I recommend: you have nexus in another state or decide to collect sales tax on out-of-state purchases to avoid any chance of legal troubles, you need to apply for a sales tax number in each state. You'll also need to charge the tax rate of the purchaser's state and not your own location. The Federation of Tax Administrators maintains a page that lists sales tax rates for the current year, along with a separate list of which states exempt food and drug sales from sales tax.