Customs & Border Patrol (CBP) requires importers to maintain a bond when importing merchandise into the U.S.  This can be in the form of a single entry bond (if you are not a frequent importer) or a continuous annual bond that persists for one year.  There are calculations for the amount of bond you will need, generally 10% of the duties and taxes you pay in a calendar year.  The minimum bond amount is $50,000 and increases in increments of $10,000.  The cost you should expect to pay for the minimum continuous bond is $300 - $600 depending on your situation.