First thing, no one automatically owns land or businesses. Everyone owns a share in the town, one thousand gold worth of share, which relates to how much money the town will pay you when it starts making a profit.
Right now it is kind of a first come first serve thing. If you spend the money to renovate a building into a for profit business, than you own said business. All of you, as share holders, have the right to build upon this land. If you renovate it into a social institution than said money spent will count as an investment, and the full price spent will be logged on top of the original 1000 investment everyone started with.
Starting off there are 50 farm, 30 business sized buildings, and 100 homes. All of them start off as needing to be renovated. Renovating a building costs half of what it would cost to build it from nothing. There is room for just as many new buildings to be built as there are ones that are build already. So 50 farm slots, 30 business slots, and 100 home slots.
Farms are 50 to be renovated, 100 to be build from scratch.
Houses are the same as farms
Businesses are 100 for renovation and 200 to be build from scratch if it is a simple business. A bar for example. A more complex business, for example a bar that has rooms enough for a brothel to be ran out of it would cost 200.
Very simple structures can be as cheap as 25 gold to renovate and 50 to build from scratch. A produce stand, for example, would fall under this category.
Mega structures cost a lot more. A casino or a resort would cost at least 2000. Renovation is not an option as no large buildings actually exist. Mega structures will not take up any of the other slots since their status would convince the king to allow them to be build right outside of town.
Simple docs which would allow for minimal trade and entrance to town via the ships cost 150 gold
A major port will cost five thousand gold pieces to construct. It would attract foreign exporters and allow for large trade contracts to be made.
So when will you start making money? Well, the more structures here, the more people will move here or travel here. The first thing city revenue goes to is paying the wages of city employees. If it cant do this, or if it can only do this, no one else will make any money. Once the costs of the city are calculated in and profits can actually be drawn, 50 percent of said profits will be decided up and paid to each person every month depending on how much each person has invested. The rest of the money will go to further developing the town.
Money made by a business will see 60 percent kept by said business for wages and operation costs(assuming it makes enough to do so), 20 percent to the owners(assuming that the business does well enough to come out on top), and twenty percent taxed(ten to the fed and ten to the town). The actual amount a business makes will be decided by me, the GM, and will be based on measuring town traffic and town activity. The more need for something, the more revenue.
All of these prices are made up by me and in no way reflect official pathfinder costs of such things.