There is no legitimate channel through which to buy CS4.
If you just have a bunch of files, you could download the trial. That would give you 30 days.
Unfortunately, this is not a one time thing. It's a workflow I am trying to arrange between two content management systems. One side is using CS6, the other side is using CS3. CS3 users need to be able to open CS6 pages and manipulate the content.
That is a workflow so full of danger that I wouldn’t touch it if could.
I'd agree with Bob: It's not a viable workflow for a large number of reasons. (1) The software is old and is no longer supported. (2) It's impossible to reliably purchase the software. (3) It's always been a very bad practice to create a workflow exchanging files between two very different versions. My friend David Blatner explains why in a post he put up a few days ago on InDesignSecrets.com:
It's like exchanging files between two databases which have different structure. Things will be lost and mangled.
Bottom line: a very bad idea.
Thanks Bob and Steve,
Sometimes a really bad workaround is a better option than upgrading a large CMS with multiple sites, especially when costs for said upgrade are not an option. :-)
I appreciate your feedback and have been looking on ebay for boxed sets... very sketchy indeed.