The NIE number, or “Número de Identificación de Extranjero”, is a unique identification number for foreigners in Spain. It consists of a letter (usually X, Y, or Z) followed by 7 digits and a control number. This number is required for foreigners who want to carry out financial transactions, purchase real estate, start a business, or obtain a work permit in Spain. It is granted by the Spanish authorities after submitting an application, usually at a police station or a Spanish embassy/consulate. The NIE number is essential for various administrative procedures and must be kept safe.

Interest rates in Spain vary depending on economic conditions and the policy of the European Central Bank. Historically, Spanish banks have had higher interest rates than the European average. Currently, the interest rates are low due to the monetary policy of the ECB and the economic situation.

When purchasing real estate in Spain, there are associated costs. Upon signing the deed of ownership, the buyer must pay VAT to the Spanish state, typically 10% of the purchase price. In total, the purchase costs can amount to about 13% – 14%, which includes notary and lawyer fees.

The average annual costs for a property in Spain can vary greatly depending on various factors, including location, property size, state of maintenance, and so on. Generally, the annual costs for a property in Spain can include:

1. Municipal Taxes (IBI): This is a property tax levied by the municipality where the property is located. The amount depends on the assessed value of the property and the rates set by the municipality.
2. Service Charges (Comunidad): If the property is part of an apartment complex or community, there may be monthly service charges for the maintenance of common areas, such as elevators, gardens, pools, etc.
3. Insurance: It is wise to take out home insurance to cover damage from fire, theft, or other unforeseen events.
4. Water, Electricity, Gas, and Internet: These are the usual utilities for which the owner is responsible.
5. Maintenance Costs: This includes repairs and maintenance of the property, such as painting, plumbing, electrical repairs, etc.
6. Any Financing Costs: If the property was purchased with a mortgage, there will be annual mortgage costs, including interest and repayments.

It is difficult to give an exact average amount for these costs, as they can vary greatly. For instance, the costs for an apartment in an urban area might be different from those for a detached house in the countryside. It is advisable to make an estimate of the expected costs based on the specific characteristics of the property and its location.