How Businesses Work
Businesses produce items which then can be sold. They work passively, but if you go a week without playing, your inventory will have filled up long ago. Unlike property, you can only buy 1 of each type of business. From there, you can upgrade 3 business attributes:

Product Quality: Changes the item your business produces. Upgrading this will increase the amount of profit you get per item you sell. Upgrading this costs twice as much as upgrading the other attributes.

Capacity: Increases your storage capacity. The limit is 2280 units. Upgrading this stat does not increase your maximal earning potential, it simply allows you go to longer between selling your inventory. With a fully upgraded output and capacity, your reserves will fill up once every 24 hours.

Output: Increases the amount of product you produce every 3 hours. For each upgrade point, this produces 20 more units every 3 hours. This is upgradeable until the output reaches 280.


Summary of Business Types
Keeping up with a long tradition of a lack of ingenuity, there appears to be virtually no difference between businesses aside from cost. That is, a tobacco plantation costs exactly half that of a sugar plantation, and produces exactly half as much income. A coca field costs 10 times as much as a tobacco plantation, and produces exactly 10 times as much income. Therefore, it makes no difference which type of business you buy first. Regardless, here are the 6 businesses, along with upgrade costs and product output:

Tobacco Plantation - Cost: 25,000 Cuban Pesos
Sale price of product: Starts at 400/100, ends at 800/100
Upgrade cost for Quality: Starts at 3,200. increases 400 every level and ends at 4400.
Upgrade cost for Capacity/Output: Starts at 1,600, increases 450 each level and ends at 5,200 for the final upgrade.

Sugar Plantation - Cost: 50,000 Cuban Pesos

Sale price of product: Starts at 800/100, ends at 1,600/100
Upgrade cost for Quality: Starts at 6,400, increases 800 each level and ends at 8800 for the final upgrade.
Upgrade cost for Capacity/Output: Starts at 3,200, increases 900 each level and ends at 10,400 for the final upgrade.

Factory - Cost: 100,000 Cuban Pesos

Sale price of product: Starts at 1,600/100, ends at 3,200/100
Upgrades: Quality - Starts at 12,800, increases 1,600 each level and ends at 17,600
Upgrade cost for Capacity/Output: Starts at 6,400, increases 1,800 each level and ends at 20,800 for the final upgrade.

Coca Field - Cost: 250,000 Cuban Pesos

Sale price of product: Starts at 4,000/100, ends at 8,000/100
Upgrade cost for Quality: Starts at 32,000, increases 3,200 each level and ends at 44000
Upgrade cost for Capacity/Output: Starts at 16,000, increases 4,500 with each level and ends at 52,000 for the final upgrade.

Produces Canned Goods
Output: 200 cuban pesos / 3 hours
Cannot be upgraded

Bribery Ring - Costs 75,000 Cuban Pesos to take over
Produces Politco Corruptos
Cost to Upgrade Output: 15,000, 25,500, 43,300, 73,700 for final upgrade. Max capacity 5 politicos every 3 hours
Cost to Upgrade Capacity: 15,000, 25,500, 43,300, 73,700 for final upgrade. Max capacity 10.