A new spur of motorway was constructed to link the new Severn Bridge to the M4 on the Welsh side of the crossing. The toll (for current prices click here) just beyond Severn Tunnel Junction railway station, is collected on the westbound side, so you have to pay to get into Wales by this route, but leaving is free! If you're travelling into Wales along the M4 you also have the option to cross via the old Severn Bridge, which offers a far better view as well as less busy tolls, and your journey will be just a mile longer. To do this, follow the M48 signs at junction 21. The M48 rejoins the M4 a few miles into Wales.