Lyn,
A couple of questions for you:
Are you going to do your collages commercially or is it a hobby? and What type of collages do you want to do?
Elements can do quite a lot of things and it is likely that you will be able to do your collages in Elements although it may take longer … things like masks are available as add ons or as workarounds but do take longer to do. This means that if you are doing it commercially PS itself may be better option for you as you will be able to achieve the result quicker. Also, if you do require features like colour matching then PS will be the way forward for you as it is not available on Elements 2.
Allen’s suggestion of downloading both sets of software and trying them out is a good way of deciding.
If you want any more information on Photoshop Elements try the Elements forum:
<
http://www.adobe.com/support/forums/main.html> then scroll down the screen until you see Photoshop Elements.
Wendy