Both Lisbon and Caparica are important tourist destinations, with a wide arrange of accommodations of all prizes. Here we provide some suggestions:

Hostels

Pousada da juventude de Almada

 http://www.pousadasjuventude.pt/en

Offers a nice and cheap accommodation service for students. 20 minutes walk to the Pragal metro station.

Hotel Colibri

 http://www.hcolibri.com/hcolibri.html.

Comfortable hostel that offers discounts for Dinosaur Eggs and Babies attendants. Close to the beach. Renting a car is strongly suggested if you chose to stay here.

Hotels

Mercure Lisboa Almada

Comfortable Hotel, close to the Pragal Metro Station

http://www.mercure.com/pt/portugal/index.shtml

Finally, both Lisbon and Caparica have a wide range of accommodations for renting via Airbnb.