Jane Austen is an author whose reputation and pedigree is so vast, that it is almost impossible to recreate an accurate account of her life and importance, without giving in to partisanship! Some critical circles dismiss Austen as the producer of 'silly Romance novels' whilst others see in her the beginning modern sensibilities of the twentieth century.
There are several features of her work that make them collectible: their fame, their controversy, and their heritage. Austen's fame as an author has since led her work to never be out of print. This is an incredible achievement for any contemporary author - and they have the benefit of being alive! Austen's success has even led to the creation of a fan movement calling themselves the Janeites, who celebrate her fiction and the world of her novels online and in re-enactments across the world. What other author save Tolkien has inspired such devotion?
Austen's controversial work however, must also not be forgot. Her very first work had to hold the by-line 'A Lady' as it was still mould-breaking for a women to take up the pen and to make a living writing! The subjects of her books too, albeit romances, are also controversial: they criticise the male-dominated society of Regency England, and seek to re-address the role of women in contemporary society.
For the collector, her heritage is perhaps of unique interest. By this I mean that, by collecting and studying her editions, I believe that it can reveal a window to the world of vanity and professional publishing from its very onset circa 1800 to the present day. Her very first two novels, for example, were rejected (and only later published) and she had to pay to have Sense and Sensibility published!
As Austen is so dearly beloved throughout the world, and has single-handedly changed the face of modern literature (and almost creating an entire genre all by herself!) then it is understandable that her true first editions can be indeed expensive. A true first edition of her vanity-published Sense and Sensibility, for example, is worth no less than $34,000! However, were one able to invest in such a unique item (only 750 ever printed, and now almost all of them certainly swallowed up into private collections) then you are sure to maintain a direct link between the author's very first flush with success to the modern day.
In comparison, I would suggest looking at the history of publishers Macmillan or the more unique Gresham Publishing. Gresham, for example, has produced some very fine special editions of Pride and Prejudice in 1900, in a striking cloth bound royal blue cover, inlaid with gold illustration. Albeit published in 1900 (and a mint Gresham edition will fetch around $1000) some eighty years after it originally appeared in print, this edition can be found for as little as four or five hundred dollars, and expresses just how important Pride and Prejudice and Austen has been through the centuries.