O'Reilly dropped the regular price of e-books for Learning Perl and Mastering Perl to $9.99. I volunteered to be the guinea pig for pricing experiments. I specifically want to see if this makes it easier to get these books when access to the hard-copies is prohibitively expensive. You can get these books in Mobi, PDF, or ePub directly from O'Reilly. I'd like to do more of these sorts of experiments to get the books into as many hands as possible.
The $9.99 price is the regular price, so all existing discount and coupon codes apply. For instance, you can still use the 35% user group discount to get either book for $6.50.
These are the updated versions of the books too. All reported errata should be corrected, so they are slightly fresher than the hard copies.
Remember, the great thing about PDFs is that they don't take up any shelf space. Buy as many as you like!