I am cheap, and $25.00/month is huge!
I love Boyds and their Chemipure products, but I couldn't justify paying for that.
Why are you running it? To polish your water? For the GFO in it? You should be able to get a refillable bag and some carbon from Bulkreefsupply (and maybe some GFO too if you want that as well) and run that in the same way for a lot cheaper.
I haven't run carbon yet on my tank. I want to once my tank stabilizes, but after the waterchange this weekend, things aren't looking good, so I want to diagnose things one at a time. Once that's stabilized, I'll add a carbon bag to the back (chemipure that I had floating around, might be a few (7) years old, but should be fine) and see if it makes a difference.