i recently got a bluk berry from a WT. apparently i can get a free sample of one are the thrifty megamart, where do i locate that person or is it on a certain day to get it?
It's from a shopkeeper on the left side area, inside the megamart.
The order cycles depending on the last berry you got from him, just keep speaking to him every day. The order is Rawst-Oran-Bluk-Sitrus-Mago-Pinap-Tamato and then back to Rawst again, and so on.
And just in case you thought of the wrong megamart, it's not the abandoned megamart that becomes Acerola's trial site, but the still active megamart near Kiawe's trial mountain.