Here's where I got mine many moons ago. The wedge base incandescent bulbs that are in your ceiling fixtures are probably Type 921. At least that's what was in mine. The W9.RV2N bulbs should be an exact fit for the sockets. http://prudentrver.com/ledlamps.html#wedge
You'll have to scroll almost all the way to the bottom of the page to see the wedge bulbs and their replacements. If you click the Buy link it takes you here: http://shop.briteledideas.com/Wedge-Base_c5.htm
The W9.RV2N are $13 each. You can get better prices than that, though I've no complaints about the bulbs themselves. They're bright, though.
After I originally posted this link over a year ago, there were other Forum members who posted links to less expensive sources, so think of this link as just a backup in case others don't respond to your question.
I think there are a number of threads about LED bulbs across all the various FR forums, it would be worth a search to see what others had to say about them and who had the best prices.