I have one. Blades cost literally about ten cents. If you really want to be crazy they can actually be sharpened, but I guarantee you will spend more than ten cents worth of your time doing it.

My only issue is that I can never quite get a good smooth shave out of just them, so I end up also using one of the expensive-as-fuck three-blade cartridge jobs for cleanup at the end, but even so using it only for that makes those expensive blades last an unusually long time, too. (Wish I could find a cheap version of those, though...)