Wanted-Perception dancer or similar

Hi all,

I'm new to this world of kayaking, getting into it to help some long distance swimmers.

I need to kit myself out with all the necessary bits,would be most interested in a perception dancer as these seem to be the way to go! Would be really interested in one if anyone has one lying around somewhere they want to shift. Or a similiar model. Cheaper the better!! Any idea of anywhere selling them cheaply second hand?

Thanks!