Freestyle photo is very supportive of film and B&W photography and tries to keep their prices down. My current gambit for high-ISO is to use their Arista Premium 400 (reputedly the same as Tri-X) with Diafine developer for the speed boost to about 1600. (I still haven't gotten to this yet: I've been shooting slowly as regarded my stores of another brand: we'll see how the results are, but this film only cost me about two bucks a roll.
They also carry Neopan 1600, which looks to be running about five bucks a roll, tthat's probably about the going rate. I haven't done a lot of shopping this year, though.