Amazon.com supports the Marketplace Fairness Act.

Starting Oct. 1, you may get free shipping from Amazon, but it’ll come at a price.
The online behemoth will start charging Maryland’s six percent sales tax on Oct. 1 as its Baltimore fulfillment center comes online, the Baltimore Business Journal reports.

The state Board of Revenue Estimates estimates in December that Amazon’s sales tax collection would amount to about $50 million in new revenue annually. Including the increase from Amazon, the state projects it will collect $4.15 billion in sales taxes next year, a 5.2 percent increase.

The warehouse represents a physical presence in the state, which means Amazon has to charge sales tax. Some state governments, like Illinois and California, have treated Amazon affiliates the same as a physical presence, or enacted laws aimed at forcing Amazon to charge sales tax to shoppers from their states.
Read the full story in the Baltimore Business Journal