Charleroi is a city in Wallonia, the southern part of Belgium
Brussels-South Charleroi airport is an important low-cost airlines hub located nearby the city.
You can hitchhike from the airport by standing at the car park exit gates located near the exit. It is good to ask the drivers where they are going when they are paying at the toll gates. Many cars are going in the direction of Brussels and Lille. If you're going to the city of Charleroi, it probably makes more sense to take a bus. You can avoid the overpriced 5/6€ direct bus by taking a local bus nearby. Walk to the bus terminal for Charleroi city and keep on walking towards the van taxis parked up next to it. Walk past them until you reach a gate in the fence with a ramp. Wait until a taxi comes in/goes out (they come and go all the time), so you won't for long. Once the gate opens for them, walk out and follow the oval roundabout to its furthest point from the airport. To your left will be a yellow bus stop GOSSELIES St. Exupery. This bus goes to the exact same place in Charleroi as the expensive bus, but only costs 2€.
From the city to the motorways
If you are in the city of Charleroi and want to take the motorways to Brussels, Mons/Paris or Liège/Germany, the best way is to reach the Square Yernaux (the roundabout with the Marsupilami) and stand along the way in to the A54.