I would just go to Home Depot or Lowe's. It really depends on how esthetically pleasing you want the fixtures to look. I do not remember the price but some smaller fluorescent's where quite cheap when I got them for an old desk.
On another note some great desk lighting could be got from one of those large adjustable arm mounted magnifying glasses. Not only do you have an adjustable light source but a giant magnifying glass when needed.
edit: dang, beat to it!