Quote from jeb9999:
DDT does not have the lowest published rates.
Eagle Market Makers starts at $0.40 a side plus platform fees.
Advatage Futures starts at $0.99 a side, but drops rapidly for volume. $0.29 a side at 2,001 sides, $0.19 a side at 5,001 sides and $0.07 a side after 10,001 sides.
20,000 sides a month works out to $0.19 a side.
The per side fee for NT is to pay for the TT data feed and network. Other brokers provide NT (and other platforms) with their own data feeds and build that into their commissions.