Some are free to download. This is the largest listing of phylogeny programs on the web. A complete on-line version of the printed and only official version of the Code. Regnum Vegetabile 131. Contains links to sites of various codes, including the controversial BioCode.
Some codes are available on-line in their entirety.
Note also the nomenclatural equivalences between the botanical and zoological codes which might be worth your time to print out. Be sure to read the Curiosities of Biological Nomenclature, which includes many of the most interesting Latin names yet published.