Ok, depends on your requirements.
If you only want Internet in your apartment go with A2Z, 2Mb for 4.75+iva per month no download limits, the cheapest you will get.
So 67.26 a year, plus installation costs of around 130 euros. I've been using it and apart from the occassional outage it's very reliable
Masmobile is great if you need internet on the move PAYG at 3cents a MB. The initial dongle is €79 including €15 credit.
Don't touch Telealhama. You need a dish, which is against the community rules, and they are more expensive. If you are downstairs they illigally mount the dish on the upstairs apartment!!! So the owners upstairs would be quite within their right to cut cut if off and throw it downstairs.