I feel like I'm going through fixer at a vast rate at the moment! I use Ilford Rapid Fixer which is 1/4 dilution so am using 50ml at a time in a total of 200ml of liquid. Sometimes this is only for a single sheet of 8x10, other times I'll develop 4 or 5 at a time. I guess a dollar a session isn't actually the end of the world. My developer works out very economical at 1/20 dilution . But being from up north and as a result being a bit tight-fisted, I'm always looking at ways to save a buck
You're quite correct though! In the grand scheme of things, $1.20 or whatever it might come to to developer a single sheet (when I do one at a time) and much less than that for 4 sheets is a bit of a deal. I guess I should stock up on a few more bottles of fixer. My developer will last me a while yet!