There are many options to consider when finding an apartment in Spain.
Firstly, the cost of apartments is important but can vary due to a variety of factors. One of the biggest factors is where you want to live in Spain. In Madrid the average rent is 1221€ per month, Barcelona average is 981€ per month and in Valencia the average is 681€ per month. These are general prices but of course in more metropolitan areas the rent will be higher.
There are specific factors that affect the prices of apartments. Those include whether the apartment is furnished, central heating or air, having an elevator, and the location.
If the search is becoming too much, you can always use an apartment rental agency to help you out. It can save you days or weeks off your search for the perfect apartment, but it will cost you more in the end.
There are two types of apartments in Spain, furnished and non-furnished. A non-furnished apartment is usually on a one-to-six-month deposit which is usually 5-50% of the annual rent. Not all these apartments will include an oven or microwave or a dryer for your clothes. Furnished apartments usually include a sofa, table and chairs, bookshelf, beds and sheets, dishes, and cooking materials, and maybe some decorations. As the price increases the quality of these provided items should as well. An easy way to furnish your own apartment is to watch what other people are throwing out.
Another option is a room for rent and sharing the living spaces with roommates. Finding a good landlord and flat mates to live with might be a bit of an issue for this option. You can also live with a Spanish family if you’re wanting to work on your language skills.
Actually finding an apartment when you get to Spain can be kind of a hassle. It’s best to find a temporary space for a while before you actually move in somewhere long-term. The worst time of year to move to Spain is the end of August or September because that’s when the Erasmus students are looking for places to live. A suggested resource is idealista.com, where you can see the apartments and send an emailing telling them you’re interested