For the first time ever i've booked via the RENFE site (only other time i used Rail Europe back as long ago as 2003 for Madrid - Sevilla).
Using the excelent advice on
i decided to use English rather than Spanish and apart from it not excepting my euro currency card (which i half expected) it all went to plan (almost).
Going Barcelona - Valencia on 30/03/13 and back on 01/04/13 which is Easter. Managed to get €22.50 on the way to Valencia for a mid morning train and on way back as i don't want to be there later than noon went for the Preferente price as it was only €9 more than Turista which was €28.
Only other issue apart from card was trying to pick a seat (Preferente appears to pick it for you with no choice?) as all coaches came up fully booked but after clicking through the individual coaches a few times one of the coaches then appears as empty so you can reserve the seat, so looks like another glitch on the RENFE booking system?
So a return ticket for less than €60 with one part in Preferente and when i checked the price for a coach return the price is similar.
So my advice is ensure you check the web link on the right hand side to help booking and the normal great advice from this site.