If you buy C-41 fix and bleach in the big jugs you'll save more. The fix can be used for both B&W and colour. The bleach seems to keep. Actually needs oxygen for the process.
The only thing that seems to go off is the developer. I'm mixing my own up fresh from bulk chemicals. If I knew the developer concentrate would keep I'd buy the big bottle of that to.
If my math is right you can buy 1 gallon of the various components from B&H for about what Freestyle wants for the kit. Unlike the kit buying the Kodak 1 gallon jugs you'll have the first time cost of the starters. So the second batch will be cheaper. Assuming you replenish. Which you should for fix and bleach. Developer is the only one you might want to do one shot.
Now the best part is if you can find a local source for this stuff. Then you'll save on the shipping.