eh.. bro who u calling sis? lol, think my gender is specified under my avatar!!!
anyway, below pics: from left to right, all live rocks, and the last pic are considered dead rocks (ie. baked till become white, however can be "live" again). try googling, you'll see Tonga Branches are not cheap, and there's alot from Indon that looks really nice too, but you might wanna first ask what you wanna keep, cos might have limitations on coral placement compared to flat pieces.
Coraline algae doesn't grow w/o water and time, so if it contains coraline algae chances are that it is already a live rock, but careful of the pest/parasite that may embed on newly purchased live rocks, such as pest anemones, crabs, etc, that's y some ppl prefer baking their live rocks completely b4 using them, however doing so will also kill off any bacteria/pods that resides in it.
If your want a giant type of branch like rocks, y not try getting various branches and combine them together to make it look like a bigger piece?
Hope it helps.