Impulse buys usually suck. In my experience anyway...I've been sucker to that as well.
I use minimal live rock with an open design plan, and make sure none of it comes too close to the glass so I can get a net all around the rock. This time I made some cool arches, so I used zip ties to secure the rock. They can't hide on me...muahahahaha!!!
Take a look at the last pics I put in my tank journal so you can see the rocks if you want. I should take a top down shot of the rocks.