To Find a Guild Hall Plot.
I hadn't created a guild since 2001. So I was not prepared for the hassle of equipping a modest guild hall. Finding the merchant in the Residential area is easy. Make sure you're carrying some money as noted above. Buy your gu ild hall choice and writ. I got the writ out of Daybreak Cash.
Then the search began. Bottom line. Real Estate plots are labeled Type: Player or Type: Guild. I spent a truly lovely hour getting irritated in going from plot to plot. After finally losing my cursor and just heading south I found GUILD HALL plots. They were not on my maps at all at all. The one I found was to the west of the residential area.
May the Ladies Luck and Sophia guide you.