In the newbie thread I linked earlier there’s a link to the Austrian economics links at Mises WIki, which compiles all the relevant links to “what is Austrian economics?” “What should I read first?”, etc.
As for Economics in One Lesson, there is also the PDF of the 2007 print as well at the Mises Wiki page…but as I was saying here I would go for the 1978 edition. (Which you can find a link to at the bottom of that thread).
However, as an opening text, one might actually do better with How an Economy Grows and Why it Crashes or Lessons for the Young Economist. (Uncoincidentally, those are actually the three econ texts listed here):
Two books everyone must read
(one might also check out the list of reading lists)
However…Here was my