i don't know anything about depth finders and i am wanting to get one.  can i mount the skimmer transducer to my trolling motor?  

For most yes, but you need get the trolling motor base adapter for it.  I think they are less than $10, been a while since I bought one.  It's just a curved piece that's mounts onto the motor with a large clamp and has the two ears on it to mount the Xducer on.

Sore,

Yes, there is a plastic piece that you buy to mount the Transducer on, then a large ......looks like a host clamp use use on auto is used to go arounf the bottom of the trolling motor.  Simply tighten it up until it hold firmly, cable tie and tape the wires to the shaft for neatness.

I think i got my braket for Cabelas.......yes it was cheap like ben said.

Kid

these guy's are right about the bracket

when You  mount it if you tape the cord down your shaft like most of us do make sure you leave enough play where the bottom swivel's so you have full range of motion

If you are using a Lowrance or Eagle product, you do not need to buy the adaptor. You can go to Lowes or Home Depot and get a hose clamp for a dryer hose. They are around 3 bucks. Most are made from stainless steel. Just turn the supplied mount for the transome the correct way and as you tighten the screw, it will cause the mount to curve with the t/m base. You may be able to do this with other MFG as well, but can not speak from personal experience. I do know that the steel clamps hold better than the plastic ones.