Shipping charges are determined during checkout and are based on the shipping method selected. Standard shipping charges are not as expensive as expedited shipping charges. Previously placed orders can be tracked as well: Track my order.
Many items shipped from Amazon.com are actually supplied by 3rd party sellers (not Amazon itself). 3rd party sellers in a state other than your own are not required to charge sales tax. Amazon IS required to charge sales tax on items coming directly from Amazon in most states as shown here: States Subjected to Amazon Sales Tax.
Returns and Refunds
Smoke Home & Garden items ordered through Amazon and most 3rd party sellers on Amazon offer returns for items within 30 days of receipt of shipment. The details of their return policy can be found here: Return Policies and Returns and Refunds.