I have a base-ball sized chunk of green macro algae available. I'm not sure what type it is since it grew right out of my live rock. It can be seen just infront of the galaxy coral in this pic.
$5
Its not attatched to anything but Im sure if you stuck it between some rocks it would take hold.
I can bring it to the meeting today if anyone is interested if you let me know before 11:30 am. I could probebly throw in some Prolifera caulerpa as well.
-Diana