The sales are announced at the link that was posted above. He only does sales every so often. You can't just "order" one from a site, you have to wait until an actual sale night (1-2 per month). Then you have to make a choice on which one you want, what type of tube/carto, etc., then send a PM to jonboyusmc as soon as he posts in the lavatank
thread on sale night. Too early and your pm won't count.
As for the tankless list, I have actually been wondering exactly what it is and how to get on it, myself.