Mattress Recycle Fee
Some states (CA, RI, CT) require retailers to charge a mattress recycling fee when a mattress is purchased in their state. This applies to online purchases shipped to those states as well.
The amount of the fee is set by each state. The fees fund the states' mattress recycling programs which helps keep bulky items out of landfills.
You can learn more here at the Mattress Recycling Council.