You've spent four levels building the framework: net worth, assets and liabilities, cash flow, good debt. This level applies all of it to the most common way to get your first real asset: buying a flat to rent out. You can check every number in this level yourself in this site's rental yield calculator. In fact, they're built using its own default values.
The most common mistake when analyzing a deal is looking only at the purchase price. The real total investment adds up three things: the price, the renovation (if needed), and the purchase taxes and fees (transfer tax, notary, land registry), which in Spain usually run around 8-10% of the price.
The rest of this level will be available very soon.
