* Bison Books and Penguin have reissued dozens of 19th-century and PGA SF novels.
* Other titles are fairly easy to find at new and used booksellers. In the 1960s and '70s the now-defunct New English Library reissued some PGA SF titles as part of its SF Master Series, edited by Harry Harrison and Brian Aldiss. In the mid-1970s, turn-of-the-century SF scholars Douglas Menville and R. Reginald republished 62 SF books from before the Golden Age with the Arno Press. Also in the mid-70s: Lester del Rey republished a half-dozen PGA SF novels under the aegis of The Garland Library of Science Fiction; and Sam Moskowitz republished 23 "classics" of late 19th- and early 20th-century SF with Hyperion Press.
Alas, some Dream-Age SF novels are impossible to purchase for a reasonable price. Money is no object, you say? Useful websites are AbeBooks and the bookseller L.W. Currey.