A template is a PHP program used by WordPress to format information in Pages, Posts and other record types in the database. The template retrieves the (mostly) unformatted information, sorted or filtered if necessary, and arranges it for the screen by inserting the necessary HTML codes.
I strongly suggest you start by reading the parts of the WordPress Codex that are for beginners. You could start here:
I also recommend 'WordPress for Dummies'. I started with it and it was a great help.
You mentioned color coding based on price, so I imagine you will want users to be able to sort by price or item name and maybe other factors. This suggests that you should use Posts in the database to contain the information about each item.
Since you said you have multiple pages, I am guessing that items are grouped by some category. That also indicates that you should use Posts.
You have never mentioned what else might be on the site, but I suspect that there will be other content that will change from time to time. Depending on the amount and the frequency of change, this could also indicate use of posts.
You have a lot of background study to do before you make a final decision. Things that sound very simple are often not easy to implement in any website, but WP should give you a good framework to start.