I spent $0 on seller's permits in 31 states. In Washington, it cost me $90.

Most founders I talk to assume a seller's permit costs money. Some assume it costs a lot.

The reality is simpler and stranger than either: most states give them away for free, a handful charge anywhere from $10 to $100, and a few have hidden costs that show up after you've already registered.

The majority of states, 31 of them, charge nothing to register. California, Texas, New York, Florida, Georgia, all free. If you're selling in those states, the permit itself isn't the obstacle. Getting around to registering is.

The states that charge fees: Washington is the most expensive at $90 annually. Connecticut charges a one-time $100 fee. Arkansas and South Carolina are $50. Wyoming is $60. Oklahoma is $20 plus $10 per additional location. Rhode Island charges $10 and requires annual renewal. Most others fall somewhere between $12 and $30.

A few things people miss. Ohio charges $50 for in-state sellers but nothing for out-of-state sellers. Tennessee does the same at $15. Some states require a security deposit on top of the registration fee, California and Missouri among them, which can be significant if your sales tax liability is high. And Washington's $90 is just the state license. Local permits stack on top.

The permit itself also isn't the same as your business registration. One is filed with the Secretary of State. The other is filed with the Department of Revenue. Two separate processes, two separate agencies, and missing one doesn't excuse you from the other.

If you've crossed nexus thresholds in new states and haven't registered yet, the permit fee is rarely the reason to delay.