SaySomethingIn is an audio only language course, the main goal of which is to promote the use of Welsh in Wales. As such, the beginners course is free, and the rest is available for £5 a month (during which time all of the lessons are available for download, so in theory you could get all of the material they have for only £5). They also teach Spanish, but this course is significantly more expensive (though still less expensive than similar courses such as Michel Thomas or Pimsleur).
I personally rather like the course; the focus on speaking and listening meant that I was quite quickly able to become conversational in Welsh. I just thought I'd give it a mention in case there was anybody here looking for resources for learning an endangered language, from England's oldest colony.