first car for making a custom car

hi,i'm a mech. engineering student from Turkey.I want to start building my own car.I'm thinking to buy a second hand old car and work on it.I'm able to find place,equipments such welding machines exc.In here you can get with approximately 5000$ 90's toyota's ,old clios,old american cars such as nova's,and old turkish cars with fiat engine and same design,old hondas.I want to work on an american car.But now i'm so faraway from the subject ,i don't know where i have to start what i have to do.But i'm learning few things about cars from my study and also i like to work on them.Anybody can show me the way?
thnks...
baris..