Both pretty obscure looking from the outside. But you know, you can't judge a book by the cover... because check out the insides.
Ship that sailed to mars:
East of The Sun And West of The Moon
Both are about $25, so not cheap. If you can only pick one I would go with East of the Sun and West of the Moon. I think the images are quite a bit more beautiful the Ship that Sailed to Mars, and the East of the Sun is a compilation of Northern fairy tales, where Ship that Sailed is one story.
The second images from East of the Sun were done in 1914. I amazed at that because they seem so different from that time period. I plan to use both of these books with the kids' homeschool curriculum next year.