I use it before blow drying and again, right before I use my straight iron. I buy it at Trade Secret.
It leaves my hair soooo smooth and shiny... actually looking like it was healthy LoL
(and it really isn't... the highlighting is so rough on my hair...)
On the cheap side, Aussie 3 Minute Miracle is great for a deep conditioner, and they have a nice leave-in as well. But I definitely agree with the Biosilk rec!