Better DO NOT attempt to drive in Barcelona. It's not so crazy that other cities (Madrid is worse, for instance), but there is VERY little parking available. And when I say very little, it means really very little, and in addition nearly always you have to pay for it!!
In most streets on the city center you are allowed to park only a maximum of a couple of hours, and this will cost you a few euros (except on festives in most areas). There are color codes: blue (regular fare), green (special area for residents, very expensive if you're not), orange (for special uses). You can always park in the underground parking lots (there are many of these)... but they cost 2€ per hour or more, so taking a taxi will cost you not much more, and with less hassle. You can go anywhere by metro or regular city buses. The metro is easier to navigate, but if you take the buses you can do some sightseeing at the same time.
There used to be a good option for people visiting Barcelona as daytrip: METROPARK “Park and Ride” service. However, due the deconstruction/building works at Plaça de les Glòries Catalanes this option is no longer available.
In Barcelona it is best not to have a car and rely on the subway/bus/walking to get around. It is a very walkable city. But if you have a car and must find parking...
I don't know how accurate the online parking services are but it's worth a try. Here's one from Parkopedia.com. They also have mobile app versions for a variety of mobile devices.
When I stayed at Citadines Aparthotel Ramblas in Barcelona a long time ago, I remember them having offers for fee-based parking. I don't think it will be €10/day since it is city centre.
There is absolutely no reason to have a car in Barcelona. Everything you'd want to see is accessible by public transport. Not only that, but traffic and parking are such that having a car is a nuisance and a big disadvantage.
That said, a rental car can be very convenient if you want to travel outside of Barcelona. And here is my tip : Rent the car outside of Barcelona as well, thus saving the frustration and time of navigating Barcelona streets and traffic.
If planning to go towards Girona/Figueres/France then rent the car in Girona - either in the town itself or at the airport. The town option has the advantage of being easily accessible from Barcelona by train - the best and cheapest public transport option, whereas you have to take a bus from Barcelona's bus station to get to Girona airport. The airport option has the advantage of the car rental agency being open long hours, as opposed to the relatively short hours they are open in town (especially on weekends). It is always better to rent the car in town if the pick-up and return hours are compatible with your itinerary, as you save time.
If planning to go in another other direction, BCN airport is the best option to pick-up and deliver as public transport to BCN airport is excellent - both by bus and train - and the car rental agencies are open long hours there (usually 24/7).
I made a mistake with my car hire this time in Barcelona. The car hire firm I'd selected is not based at the airport as I believed. Instead a courtesy minibus takes you to an industrial estate ten minutes drive away to collect your vehicle. I'm an experienced driver, but I simply could not find my way back to the car hire firm at the end of our trip, and I had to pay an airport taxi driver 20 Euros to guide me to the site. Another time I'll make sure the car firm is actually AT the airport!
I was meeting a friend in Barcelona airport for our southern "Spanish" roadtrip, so I arranged to rent a car with Europcar prior to my.
The kiosk is located after exiting customs and was very easy, efficient and convenient to get to. I arranged for and pre-paid my rental via the internet prior to arriving Barcelona. At the kiosk I was aksed for my license (I also had an international drivers license), my reservation information and my credit card information. I was traveling with a friend and he also wanted to drive, so he paid the additional driver fee that was not included in the price.
The cost was around $285 for our 7 day rental with taxes. There was an additional fee charged ("airport fees") at the end of the rental, which they did inform me about for around $65. The price was for a two door stick-shift Hyundai with unlimited mileage.
The staff was friendly and informative and we were given our key 10 minutes after all the paperwork was done along with a map (we had a navigation system though) and instructions on where our car was parked and how to exit.
They rent a GPS for an additional charge if you so need it.
I'd definitely rent from Europcar again in Barcelona or anywhere else in Europe as they have been the least expensive and most reliable company.
Please note that I get an excellent rate based on the time of year I was traveling which happened to be around the Christmas/New Year holiday.
this page tells you all parkings in Barcelona with prices
when I go I pay the hotel or sue the cheaper parking by bulevar rosa shopping center in exaimple.
HOpe it helps on your choices
Valencia is very nice, see Carmen neightborhood its lively with night life.
this site tells you good on it
a bit south at El Saler is the area of the rice of Paella, just around the Albufera national park
and some attraction to do a paella in a boat!
The water will be ok in those dates depends from where you are coming from. Should be in the 20's C out the water cooler.
renting a car is glorious, see www.autoeurope.com or www.kemwel.com
and for route planning the Spanish gas company similar to Michelin is Repsol
Then you have your days in Barcelona, I love the Exaimple are great architecture all around you and close to everything. park and shop at bulevar rosa
You have it all, enjoy your visit.Hope it helps