I only use top quality Pastels Pencils and Pastel Sticks for my Art Work. These include the following: Faber Castell, Derwent, Carbothello, and Conte Pencils. For the sticks: hard, Conte Soft, Unison, Sennilier, Jaxell extra fine, Faber Castell, Windsor & Newton Artists Soft Pastel.
The Conte Hard Sticks are always used first as an under painting, I do try to leave some pigment of the under colour visible to the top layers. There is no detail in the under painting, just tone, the laying down of lights and dark. The detail is left till the last layers.
On the useful sites page, there's a list of the most economical places to purchase materials from.
I do not recommend the use fixative of any kind, as it has a tendency to ruin work; there is a significant colour change, the pastel colours become washed out and the whites resemble a spattered mess..........Lesson learnt !!!!