Photoshop 1.0 probably won't give you much functionality with digital scrapbooking, unfortunately. Layers weren't supported in photoshop until version 4.0 and most brushes you find on the web for decorating are for versions 6.0 and up.

GIMP is a decent program, and has much of the same functionality as the more expensive graphics editors. You can find it here: http://gimp-win.sourceforge.net/

Aside from that and using the 30 day free trials found on websites, you can check e-bay or used-software stores. A lot of times you can find at least a decent copy of PSP 7, possibly Photoshop 6 for around 50.00 or so