Under the Obama administration the US relaxed rules on citizens traveling to and spending money in Cuba. They even reached an agreement to put air marshals on planes so air marshals could party in Havana and Americans were allowed to bring back unlimited Cuban cigars from their travels.
The new Trump administration though moved to crack down on the ability of Americans to travel there. These travel restrictions required Americans to go as part of organized tours and forbade spending money anywhere owned by the military. Now get ready for a new round of even tougher restrictions on traveling to Cuba.