It's much cheaper to leave them both off.
If you're ok with just the blower running then odds are you'd be ok without it running as well. A ceiling fan is much more economical and vastly more sensible. In many (if not most) cases, running the blower continuously will reduce the indoor comfort level. It not only acts to introduce heat into the conditioned space but moisture as well. You may get a spurt of minor relief by the low velocity air movement, but in short order it'll have defeated its purpose.
hvacrmedic