I have a powerpoint presentation that is 108 pages. It is a simple presentation with no bells and whistles. I purchased a template to try to spruce up the look of the presentation. Do I have to recreate each page with the new template or is there a way to take the entire presentation and incorporate it in the template at one time? Thanks in advance for the help.

When you apply the template it's going to change every slide. The potential for a huge mess is considerable.
What you ought to to is go into the master view of the desired template and change the fonts to the ones in use. Save-as a differant title and then ap0ply your new one. That will minimize the mess. But there is no telling what the end result will be.
Be certain to keep an original in case it goes badly!

You can quickly see what kind of outcome you're gonna get when you copy slides in slide sorter, and paste them into a ppt that is using the new template. They should all change-- if you set up your originals using proper titles and bullets, etc.

You will have to take a sweep through all the slides and clean them up-- if they were set up cleanly initially, you'll only have minor tweaks to do.