Pretty sure the $1 per gallon sale was over on Saturday...I was trying to get another 40 before it ended, but no one had them in stock. I actually got 2 of them when the sale first started, but I used them to upgrade my snakes' vivariums.
bknapp, I like the new 'scape a lot better... The flat pieces are a plus - I have a lot of rounded, boulder-type pieces that are very difficult to stack. Usually my method is similar to what gmoney said earlier... let the rocks stack themselves. I find that usually if I put one rock on another and move it around a little, turn it on it's side or backwards, etc. that eventually I'll find the sweet spot where it will sort of "lock" into place with the other rock. If I want to create a shelf, I might hold a flat rock so it overhangs the ones below it and then use a couple heavier rocks to hold it down. Just go for a solid structure that's not going to collapse when a snail wedges itself between your rocks and glass. Hopefully, by this time next year no one will be able to see your rocks with all the coral on them anyway. :)