The home site for the product is:
although you will see that only versions 4 and 4 deluxe
is advertised (look under "Print Creativity" or "Digital Photography"), which, of course, you could go for. Prices: version 4 - $ 29.95; version 4 deluxe - $ 49.95.
However, If you are really intent on getting version 3, you could try out this site's customer or technical support (http://www.novadevelopment.com/support/customer_service/index.html
I did a quick Google search. If you're not able to get version 3 from novadevelopment's site you may be able to get it from sites that (still) advertise it, like:
Of course, it could be that the sites / site information is old and no longer relevant.
Be sure to check the system requirements for version 4 and 4 deluxe, should you opt for those versions (given on-screen on novadevelopment's site). Furthermore, it appears that versions 3 (no longer in development) doesn't work with Windows 7 (reference: http://www.softcity.com
), and that some users are of the opinion that version 3 is better than version 4 (reference: http://220.127.116.11/contribution/1cDMxMzN/view/please-help-photo-explosion-deluxe-version-3-is-much-better-than-version-4
I wish you all the best.