I'm in Colorado and I had to pay $66 up front. $50 is a deposit and $16 is the fee every two years. I see that California doesn't have a fee but I know other states do.
TaxJar will register for you in the States that you need for ~$100 per state, plus their fees (https://www.taxjar.com/state-registrations/) -- I'm sure Avalara does something similar but that's ~$5000 that a small business probably won't have.
Colorado has home rule cities with their own tax license, rules, submission. Even due dates van be different per municipality.
It's a system designed ages ago, not only pre-internet, but even pre-car.
For internet businesses it's really unworkable to require they submit anything other than state sales tax but even that is onerous due to registration fees and old and nonstandardized submission systems.
TaxJar will register for you in the States that you need for ~$100 per state, plus their fees (https://www.taxjar.com/state-registrations/) -- I'm sure Avalara does something similar but that's ~$5000 that a small business probably won't have.