Flapping "for Sale" sign, need design help
 

I'll be selling my house soon and will have a small billboard-shaped
"For Sale" sign (about 4 feet wide) by the side of the road. I want to
'attract the eye' of passers by, and thought of the idea of putting
some flags on the top of the sign and having them rapidly flap back and
forth about every 3/4s of a second or so.

I'm looking for suggestions for motor size (and 'type').
Unfortunately, the road side is some distance from the house (and there
are other considerations) so I can't run AC out to the motor so I guess
this contraption will have to be DC powered: any suggestions about
powering the motor would also be appreciated. Need this contraption to
work for about 8 hours at a time.

Christopher A. Steele