Many European countries are known as very expensive places to live. Brussels is an important capital but is not as expensive as can be for instance London or Paris.
You just have to take in account that the accommodation is what is going to define how much you will need each month.
You can find rooms from 250€ per month or you can look for something more expensive as well. The price of the accommodation will depend on the zone and the infrastructure that you will have.
To the accommodation cost you should add at least 250/300€ more for the daily expenses such as transport, supermarket...
