I ended up purchasing live rock locally, and was able to pick my pieces. The gentleman who helped me was really nice and threw in a few hermit crabs, a few snails, a brittle star and a shrimp for me for free, aside from any hitchhikers (and he pointed me to a piece with a cute little feather duster on it). The rock was $6.99/lb and a very nice purple color. It had nice holes in it and was fairly light, so I got 5 good sized pieces, totalling 21 lbs.
He also sold me the caribsea live sand, and a few cups from his tanks to help it kick off. He cleaned the dead sponges off the rock for me, and helped me inspect it for glass anemones before I left the shop, in a seperate tank he uses for holding customer purchases.
He was very nice and helpful! I was very impressed, and I am glad I went the local route. I was very interested in the tampabay rock, but terrified of the hitchhikers.