I snagged some used encapsulated polystyrene dock floats on the facebook marketplace back in the spring. Got five 4x8x1 and one 3x4x1 for $200. They were a bit beat up from spending a number of years on the Osage, but they're plenty good for my little puddle.
I like the 1' thick floats because they keep the top of the dock close to the water.
