I went to Lowes to get a couple things and wandered by the outdoor lighting area. I always have an eye out for yellow tags- and spotted this.
They are discontinuing these 100 watt cooper mercury vapor dawn to dusk lights. $54 down to $9.85 (with bulb)! Whats funny is that this is only for the white ones. The brown ones were down to $34. UNless you go to a different Lowes and the brown ones are $16. Seems like random pricing...
I figure that if I end up not liking merc vapor, I could rewire the bulb socket and just screw in regular compact fluorescent floods.
I ended up snagging 5 for outdoor lighting aroudn the barn and under my new "tractor-port" that I built on the front of the barn. These are not as energy efficient as sodium, or T8 fluorescents for that matter, but a lot better than incandescents for sure.
I think the sku is 127118, FYI. I got 2 different stores to unscrew the demo model and sell me that as well.