I use IB for a lot of trading, but these TLT trades, in my opinion, are too expensive there so I use Tradier for them. However, I made these trades at IB before I switched to using Tradier so I can give you real numbers on the commission differences. Over several hundred contracts of TLT butterflies at both brokers, my average commission per contract at IB was (EDIT: $0.5041....not the $1.138 I posted originally) and my average at Tradier is (EDIT: $0.11925...not the $0.214 I mistakenly posted originally. Tradier does charge a $10/month for Tradier Pro, which is spread across many other contracts for me. But even if you only traded these TLT trades at Tradier and you only did 15 butterflies per month, it would cost you around (EDIT: $14.31 commission...not the 25.68 I originally posted) + $10 monthly fee = $24.31. Whereas at IB, the same trade would be roughly (EDIT: $60.49...not the $136.56 I originally posted). Those are total costs to open + close just as a comparison of the difference