I called and offered $100 just for the Red Zone Channel, but was told they couldn't sell it as a standalone. I mentioned that buying the Madden 25th anniversary edition for $100 included streaming access to NFLST, but I didn't feel like dealing with hooking my tablet/phone up to the TV via HDMI every week and I'd much rather give them the money.
They offered NFLST for 1/2 price, but I still said that was more than buying Madden. So, they ended up offering $15 off a month for a year PLUS 1/2 price NFL ST.
Sold... looking forward to kickoff in September!