u can get frags from fellow reefers as what peacemaker said. most are happy to give/sell/trade with you. if u prefer larger rocks, u can go to LFS and LFF. henry at marinelife occasionally bring in zoos. GO always have zoos, sometimes dont have nice ones, sometimes have those gems. IWARNA also have zoos. But sometimes not nice. I guess it is just luck when u happen to chance upon a nice specimen in a shop, then u faster grab it
One thing about zoos, they usually have alot of pests. when u buy zoos, keep a sharp eye for any nudibranch, spiders, snails etc etc. remove thoes visible ones with plyers or toothpick or ur finger nails haha. but be careful not to hurt the polyps. You can dip it in a bucket of freshwater with lugols iodine solution for a few minutes to kill all pests too.