I used Suave Naturals shampoo for my last sulfate wash -- I think it was less than $2. Another good option would be a V05 shampoo; I think those are under $1.
CG since July 2012!
3a; mediumish porosity, medium/coarse, high density
Cleansers: Suave Naturals, VO5, SM shea butter shampoo, TJ TTT shampoo
Conditioners: GVPCB, Tresemme Naturals, TJ TTT
Stylers: LALS, La Bella gel, SM curl milk, coconut/olive oil