We are looking to rent a car in Spain (Barcelona) and drop it of in Portugal (Lisbon). Some people h

We are looking to rent a car in Spain (Barcelona) and drop it of in Portugal (Lisbon). Some people have mentioned that booking through some of the international car rental companies from home (Australia) is more expensive then booking through a local spanish company. Any suggestions? We are looking for a very large car (4 adults, 2 child seats and luggage space) so not sure that all companies will offer what we need. Any advice?
There is little difference if picking up in one country (Spain) and dropping off in a second country (Portugal). You'll pay a steep drop off fee. Now as far as renting the car, I highly recommend Auto Europe and Kemwel. They are brokers that will tru ti get you the best deal. We've been using Auto Europe for at least 30 years without any problems (2 to 3 times year).
We are huge Kemwel fans. Call them on the phone and they will work with you and talk you through any questions you have. They will also beat any price you find-- so do your homework before calling. We always use their 'no deductible' price-- it just brings us extra vacation peace of mind. Our credit card covers us, too... but we like having separate coverage.