Getting here by air:
The easiest and cheapest way to get here is flying in to Reus. If you can get a flight with Ryanair it will take you to Reus airport which is just 10 Kilometers away from Salou. I understand that with every Ryanair arrival there is a bus that takes you from the airport to Salou and one of the stops is just a five minute walk from the apartment. Of course you can also rent a car right in the airport and drive to Salou yourself.
You can also fly in to Barcelona which is 90 Kilometers north from Salou. To get to Salou from Barcelona you can go by rented car or by train. To go by car you can easily get here on the A-7 expressway.
Getting here by car:
The best road to get here is the A-7 expressway. You must get off the expressway on exit 35. Follow the signs for Salou and you will be here in a couple of minutes.
If you will be driving I can give you detailed instructions for getting to the apartment.
Getting here by train:
From Barcelona airport you must take the shuttle train (usually with a 20 minute frequency) to Barcelona Sants which is the main train station in Barcelona. There is usually about eight or ten trains every day that stop in Salou and the fare can cost between 6 Euros and 14 Euros depending on how fast and comfortable the ride is. It can take you between 1 and 2 hours to get here by train.
From the Salou train station you can take a taxi to the apartment or you can do a five minute walk to the beach where you can take a bus that also stops five minutes from the apartment.