Fusion are expensive anywhere, but they are a good blade. It would seem to me that 3 a week is really high unless your beard is extremely heavy and coarse. For my part, when I was shaving my face, or most of it, a Fusion or M5 blade would last a week easily. Now, just shaving the remnants on the scalp--three weeks easy. I have found that spraying the blade down w/ rubbing alcohol, 91%, after shaving seems to help too. Others have stored the blade in a small bowl of olive oil--both methods based on preventing the blade from deteriorating in the damp air.
And twice a day shaving, I haven't done that although I think a couple of guys do. Once a day is enough for me.