Before discussing the "free" aspect, it is crucial to understand what this DLC actually contains. Developed by Halcyon Media (known for high-detail German maps), this add-on is not just a typical bus route.
. While the official add-on is a paid product, the OMSI community often provides free "freeware" alternatives or modifications, such as the Wuppertal_634 map OMSI 2 Add-On Wuppertal free offline