Here's NinjaTrader's pricing guide. https://ninjatrader.com/PDF/ninjatrader_futures_commissions.pdf I have the Lifetime License, so on Micros I pay ~ $0.82 round trip per contract and ~ $3.78 on E-minis.
I'm with @Buy1Sell2 now. I think we're going to see a down day. We're just about to retouch the gap fill line on SPX. If it breaks through, which it looks like it will, I think the 92 is not out of reach, and possibly even 80.75 or lower.