We got our lights at Home Depot.... cant remember how much $ but they are a
string of 3 round lights with a few feet of cord between them. My husband
used plastic strap ties to afix them to a piece of pvc pipe and we lay it
along the edge of the pond bottom that abuts our deck.

The nice thing about it is that every so often I just pull on the cord and
the whole pipe comes up so I can use a brush to clean off the lenses. Then
I just lower it back down to the bottom and use a pole to adjust the light
heads so they shoot across the bottom of the pond.

We put them on a photosenor timer that was real cheap and it turns them on
automatically when it starts to get dark and they stay on for 2-1/2 hours
(you can adjust it to any time you like).

We've had them for 2 years now and no problems and no burned out light
bulbs. The white pvc quickly grew over with algae so it is invisible.

Another positive thing about lights at night is that I can see the turbidity
of the water. It shows up so well at night, where during the daytime it
looks like the water is crystal clear, then at night you can see all the
stuff that is suspended in the water. The fish seem to enjoy the lights too
and cruise around excitedly while the lights are on.

Good luck and happy ponding!
wendy in Oregon