There are some buses that go between LV and Laughlin, but they involve some (not much) money.
Gray Line Tours is one option -- there is a 10% discount (at least usually) on a tour (check to see if this is the case in regards to Laughlin as well) trip by showing an Auto Club (AAA) card.
Plus there is another company that does bus tours which often advertises in Las Vegas Magazine, so check into this! Info on this company is in the paragraph that is below!
See the thread (in the Las Vegas (General) message board) called "Free Laughlin Tour From Las Vegas" (from December 2015) for more information.
