I've used the Brittany ferries to Spain a few times and the are good. There is a listing of the times on the web site but the only way I've found to get the prices is to go through the booking till you get to the price section and then bail out if you don't want to book. The thing is with all these bookings is that they seem to vary the prices depending on time of year and what's on at the time you want to book for and how busy it's getting. More punters and they up the price.
Cheers
John