I have read through the Seat 61 advice on Spanish trains and he talks about three options for train tickets - loco2, petrabax and renfe. I have checked out all three sites and now I'm confused. They seem to offer different options in terms of class of tickets and the prices are quite different. There are four of us traveling from Sevilla to Barcelona and when I put in four people the individual price is much higher than looking for an individual ticket. Is there one of these sites that people recommend?
Renfe is the supplier, so try them first. If there's any chance that you didn't always search the same travel date, then that can affect the price, as the lowest advance discounts sell out first. Paying with PayPal can be more successful than with a US credit card.
If the lowest fares don't have four places left at that price, then you can all be pushed into a higher price category. In that case, try booking pairs and see how close you can request the seats, but you wouldn't likely get a real block of four seats together. Petrabax in the USA has also been doing this for years with a good reputation, but their price couldn't be lower than Renfe.
Susan-
My family of 5 is travelling from Seville to Barcelona in late June. We are flying. It is a short flight and less then $300 for all five of us. Check out vueling airlines.
If you're trying to book on Renfe, you will need the help of this invaluable tutorial from TripAdvisor: http://www.tripadvisor.com/Travel-g187514-c80518/Madrid:Spain:Buying.Renfe.Tickets.Online.html
And don't even waste time trying to use your credit card - use PayPal instead.
If you can't get Renfe's website to work, then you can try the others (they have been recommended for years, but I've never used them personally).
Do compare the train prices with the airlines, but don't forget to add the time and cost of getting to and from the airport on each end.