I think Gary in his....
 
"Don't use hair spray.  Its use in cytology was discredited long ago.  The composition is usually undefined."
 
is overstating the case rather. Some 20 years ago I bought 24 random cheap hair sprays and trialed them. All did a good job, and I could not robustly tell one from the other in terms of results. The fact that the composition is unknown strikes me as irrelevant.
One problem with them is however that the spray comes out with such a force, that the material could be over the far wall before one realises if held too close, and if held an ideal distance, fixes half the bench and you with it:-)
 
The real point is of course that the formula given by Gary is so easy and cheap to make up and put into a pump spray, that there is no need to look elsewhere for fixative.

Terry L Marshall B.A.(Law), M.B.Ch.B., F.R.C.Path
Consultant Histopathologist
Rotherham General Hospital, Yorkshire
terry.marshall@rgh-tr.trent.nhs.uk