Find a car rental agent as opposed to one that owns it fleetThey usually use the big boys cars at discounted rates just to get cars on the road.Their terms and conditions are usually different.

http://www.carhire3000.com/Home.do?affiliateCode=google&label=Brand1-2YgrkRB4Qlx...

I got one from Pisa airport,took me a few minutes of head scratching and found they where using Herz cars at half the price.

I have used different online booking services but I usually return to Argus, they usually have Inter rent(Europa) or Hertz cars. I do not like the companies who bus you away from the airport. One company ( away from airport) I used were not open when I returned the car I had to leave it in the Airport parking and pay 17 Euros.

I have just booked a Daihatsu with Interent via Argus from Reus for 80 Euro  8 days. I have had this car out before its not great but the Daihatsu,s are new and I do not do much driving. Take full petrol leave back empty. Also Europa/Interrent at Reus are very aggressive in trying to sell you the optional roadside breakdown insurance, 5E a day you also need to tick it off on the Argus site if you do not want it

Well after hours checking out companies etc...... discount codes ,cash back sites etc reviews from others, I have booked through Economy car hire, and car hirer is Centrauro cost for 11 days with discount code was £79.00 but I will get stung with the full /empty Conn , and cost for tank of petrol between  60-140 euros, as it,s only a 2 door fiesta (not cheapest option) I would hope they will charge around 75-85 euros for the fuel, around 20-30 euro ripp off on the cost of the  fuel, I had a corsa in Feb and it cost me 56 euros to fill up but  how much has the cost of petrol gone up since then LOL!!!!!!!!
I could have got a cheaper price through ecarz £69.95 but with these excess charges of £350 for a replacement mirror ,£500 for minor damage,£250 a Tyre or take  the extra CDW @ £ 54 .00 on top of original price  I dare not take risk, whereas Economy car hire there is no excess etc... no ripp off 0871 10p min phone numbers etc... and you get to know who your hiring from.
I now cannot find any car hire firm, operating from El prat that are not using the full to empty conn, if you go through Europe car they state on there site, full to full, yet I read a review today on a site that yesterday a hirer was charged  full to empty and Budget etc.. are the same and cost for a basic panda etc... around £120+
So there  finger crossed I have done all I can, hopefully it  cannot be as bad a experience as February will have to see ?
Still not got a room booked,  thats my next task, this is looking like £40 + more,than same amount of night,s in February (tortosa Parc) so I might end up a extra night in my tent
I hope this post might help
Phil
PS, I still love My finca and Spain 

Last time we had a car on the full/empty lark we only used about a third of a tank. I took the gamble and filled it up myself before returning the car. Told them (Solmar) it was full and they didn't try to charge me for the tankful.

Come on boys, are you inferring Yorkshire men are Tight LOL!!!