Santiago de Compostela is a city in Spain.
Hitching out
Getting out can be difficult as there are only two roads that go out of the city, leading to many different directions.
East towards Santander, San Sebastian, France
Head out from the airport in the direction of Lugo and then Oviedo. This is the coastal road route. From here there are a lot of tourists and you are more likely to get someone foreign who is more likely to pick you up than the locals.
Sleep
Just outside of Santiago is a small town called "Monte do Gozo". Some pilgrims stop there before entering the city. It's a huge center and has almost 2000 beds. There is a frequent bus line that will take you to walking distance of the town centre. Apparently it works with donations.