On WO days I will take in 7 scoops of protein a day (5 whey and 2 blends). Breakast (2), pre-workout (1), post-workout (2), bedtime (2). On non workout days, I'll take in 4-6 a day.
I normally buy protein in bulk, but it'll probably average out to $60-75 a month, depending on WPI vs WPC, etc.