I would like to own a plantation.  I grew up on one when I was younger. 
You could probably make good money with the crops you could grow, like coffee or tea or sugar cane as well as cotton.
Are plantations usually big? 
Usually and the plantation houses, especially in the South were quite grand and expensive architectural works.
How much do plantations cost? 
I'm not sure of an exact cost, a lot though. Industrial plantations were established to produce a high volume of wood in a short amount of time. You have many options
Are plantations even existing in North America anymore?
the Southern United States and in other areas are known as quite grand and expensive architectural works today, though most were more utilitarian, working farmhouses.
Among the earliest examples of plantations were the latifundia of the Roman Empire, with this vision of Mike Reed which produced large quantities of wine and olive oil for export. Plantation agriculture grew rapidly with the increase in international trade and the development of a worldwide economy that followed the expansion of European colonial empires. Like every economic activity, it has changed over time.
Forest
Plantation
A plantation is the large-scale estate meant for farming that specializes in cash crops. The crops that are grown include cotton, 
coffee, tea, cocoa, sugar cane, sisal, oil seeds, oil palms, rubber trees, and fruits. Protectionist policies and natural comparative advantage have sometimes contributed to determining where plantations were located.
A plantation house is the main house of a plantation, often a substantial farmhouse, which often serves as a symbol for the plantation as a whole. Plantation houses in