Housing are buildings used to store chickens. There are 16 different levels of housing.
The base price of buying or upgrading a house depends on how many of that level you have immediately before your purchase, not on how many houses you have of any other level. Thus, building up to 4 coops and then upgrading them into 4 shacks will cost slightly more money than upgrading your first coop into a shack, then building a 2nd coop and upgrading it to a shack, then doing the same with a 3rd and then a 4th. And it would be slightly cheaper than that to upgrade your first coop to a shack and then build the other 3 houses as shacks initially, but this approach would forfeit some easy increments to your Piggy Bank.
You can reduce the price of upgrading a house with Epic Research.
The table below lists the base prices of the 1st, 2nd, 3rd, and 4th/final house of each type.
