I'd have to agree with the others, cus I use to have one...
if you're talking about those battery-operated "Cyclone-action" mixers. Poorly made/engineered. The friggin motor is almost submerged but the thing that spins gets clogged with shit and it rusts. You can't even seperate this piece to clean it.
ALSO cheap alternative for a shaker... (I keep losing mine) is to use an old Gatorade/Powerade bottle. You gotta use a funnel or rolled up sheet of paper to get the powder into the bottle tho.