depth/fish finder for kayak?

Anyone have any recommendations for a portable fish finder that I could attach to my kayak? Even a basic one that would just give me an idea of depths so I could find drop-offs, channels and whatnot. I'm looking for something on the lower end of the price spectrum...

i use a hummingbird 565 couple years ago paid $180. but i just saw hummingbird 535 on sale at bass pro about 2 weeks ago for $129. did'nt look to be much diferent.it was an over stock item.so it was on sale.not a bad price. i've had mine 2 full years now no problems.i power it with a 12 volt 7 amp battery also from bass pro.i payed $40.00 included charger.i go out all weekend before i charge it weather it needs it or not.

how's $85 sound?

http://www.walmart.com/ip/Garmin-Fishfinder-90/4660393?sourceid=1500000000000003260410&ci_src=14110944&ci_sku=4660393

you might have to jury-rig a way to mount the transducer...


EDIT: there is a clamp-mount depth finder called 'the fishing buddy' for $115, but the depth finder itself looks pretty low grade... the transducer is on the end of a pole-type thing. I suppose you good make that part yourself with abit of time at Lowe's. *shrug*

I made my own mount from scrapes and use an old Eagle fishfinder works like a charm.Mount sells for $38 mine cost $5 and I think it works as well.