Looks like IB is $1.82 (0.90 + 0.90 + 0.02) per side for YM for unbundled if you don't hold overnight, with no volume requirement. Over 300 contracts per month, it drops $0.20 per side. Over 1000 contracts per month, it drops another $0.25 per side. Save another $0.60-0.80 per side by getting a CBOT membership (I don't remember which one).