The best bang for the buck is probably Royal Road to Card Magic
It is hard to beat the $5 for the ebook, given the excellent contents.
However, if you are really serious about card magic you should go for the Card College
series. It is more expensive than the Royal Road, but much more detailed and much more carefully described.
For further advanced card work I suggest Card Control
by Buckley, an often overlooked book. Steven Youell has recently emerged as a fine teacher of advanced concepts, see Advanced Card Techniques
. Peter Duffie has also recently released a wonderful collection of cool moves Move Mastery 1
. And the classic Expert Card Technique
shouldn't be forgotten either.
If you are after a particular move, say the bottom deal, then nothing can beat The Artanis Bottom Deal
which was probably the first multimedia description of a move, integrating text, photos and audio. For the pass you might want to take a look at The Invisible Pass
If however, you are more looking for great plots, effects and routines, you should study Hofzinser\'s Card Conjuring
and New Era Card Tricks
If on the other hand, gambling plots and themes are your thing, take a look at Expert at the Card Table
and Angels May Shuffle but the Devil Still Deals
And that is just the tip of the ice berg.