The phrase "free trolley" refers to a transportation service, usually in the form of a small vehicle or a train, that you can ride without having to pay any money. Full definition
The Chicago Park District late last year started free trolley service to the Garfield Park Conservatory from downtown hotels. (articles.chicagotribune.com)
During the Whale Festival, local wineries showcase their recent vintages at various stores and inns while free trolley rides ferry participants between activities. (heritagehouseresort.com)
If you'd rather not walk, there are also free trolleys to shuttle you along the main street that makes several stops along the way. (johnnyjet.com)