I trade SPX BWBs so I get hit with the CBOE fees, etc. That $0.70/contract figure ropes them in but isn't the whole story. Effective commission is $1.22/contract for me on a 6-lot BWB
IB commission = 0.70
CBOE exchange fee = 0.44
US regulatory fee = 0.04
OCC clearing fee = 0.04
Total = 1.22