Returns for Apartment and Residential properties generally are between 6-8% per year of purchase price of the property.

Example
On an apartment costing 200,000 Euro, rental income should be around Euro10k-12k per year.

A typical mortgage on 200,000 apartment assuming 90% financing at 3.5% interest would cost around 900 Euro per month.

Capital Growth
Part of Budapest have experienced incredible growth (20-30%) over the last 2-3 years. Assuming that on average growth rate over the next 4-5 years are only 10% this give you a return of over E20K per year in your investment which is self financing from rental income.