Purchase some clamp on work lights & basic soft white light bulbs.
Go to school supply section of your local department store.
Get large sheets of white art/construction paper.
Clamp light to chair, facing wall.
Tape paper to wall in front of light.
Light reflects off the paper, falling on model in a nice soft even glow.
Umbrellas and lights on stands give you lots of control, but the clamp-ons with paper reflectors give you a starter setup.